FILESANDFORMATS

By default, the image format is determined by its magic number, i.e.,
the first few bytes of the file. To specify a particular image format,
precede the filename with an image format name and a colon
(i.e.ps:image) or specify the image type as the filename suffix. The
magic number takes precedence over the filename suffix and the prefix
takes precedence over the magic number and the suffix in input files.
The prefix takes precedence over the filename suffix in output files.
To read the "built-in" formats (GRANITE, H, LOGO, NETSCAPE, PLASMA, and
ROSE) use a prefix (including the colon) without a filename or suffix.
To read the XC format, follow the colon with a color specification. To
read the CAPTION format, follow the colon with a text string or with a
filename prefixed with the at symbol (@).
When you specify X as your image type, the filename has special
meaning. It specifies an X window by id,name, or root. If no filename
is specified, the window is selected by clicking the mouse in the
desired window.
Specify input_file as - for standard input, output_file as - for
standard output. If input_file has the extension .Z or .gz, the file
is uncompressed with uncompress or gunzip respectively. If output_file
has the extension .Z or .gz, the file is compressed using with compress
or gzip respectively.
Finally, when running on platforms that allow it, precede the image
file name with | to pipe to or from a system command (this feature is
not available on VMS, Win32 and Macintosh platforms). Use a backslash
or quotation marks to prevent your shell from interpreting the |.
Use an optional index enclosed in brackets after an input file name to
specify a desired subimage of a multi-resolution image format like
Photo CD (e.g. "img0001.pcd[4]") or a range for MPEG images (e.g.
"video.mpg[50-75]"). A subimage specification can be disjoint (e.g.
"image.tiff[2,7,4]"). For raw images, specify a subimage with a
geometry (e.g. -size 640x512 "image.rgb[320x256+50+50]"). Surround the
image name with quotation marks to prevent your shell from interpreting
the square brackets. Single images are written with the filename you
specify. However, multi-part images (e.g., a multi-page PostScript
document with +adjoin specified) are written with the filename followed
by a period (.) and the scene number. You can change this behavior by
embedding a %d format specification in the file name. For example,
image%02d.miff
writes files image00.miff,image01.miff, etc. Only a single
specification is allowed within an output filename. If more than one
specification is present, it will be ignored.
When running a commandline utility, you can prepend an at sign @ to a
filename to read a list of image filenames from that file. This is
convenient in the event you have too many image filenames to fit on the
command line.

OPTIONS

Options are processed in command line order. Any option you specify on
the command line remains in effect for the set of images that follows,
until the set is terminated by the appearance of any option or -noop.
Some options only affect the decoding of images and others only the
encoding. The latter can appear after the final group of input images.
This is a combined list of the commandline options used by the
GraphicsMagick utilities (animate,composite,convert,display,identify,import,mogrify and montage).
In this document, angle brackets ("<>") enclose variables and curly
brackets ("{}") enclose optional parameters. For example, "-fuzz<distance>{%}" means you can use the option "-fuzz 10" or "-fuzz 2%".
-adjoin
join images into a single multi-image file
By default, all images of an image sequence are stored in the
same file. However, some formats (e.g. JPEG) do not support more
than one image and are saved to separate files. Use +adjoin to
force this behavior.
-affine<matrix>
drawing transform matrix
This option provides a transform matrix {sx,rx,ry,sy,tx,ty} for
use by subsequent -draw or -transform options.
-antialias
remove pixel aliasing
By default antialiasing algorithms are used when drawing objects
(e.g. lines) or rendering vector formats (e.g. WMF and
Postscript). Use +antialias to disable use of antialiasing
algorithms. Reasons to disable antialiasing include avoiding
increasing colors in the image, or improving rendering speed.
-append
append a set of images
This option creates a single image where the images in the
original set are stacked top-to-bottom. If they are not of the
same width, any narrow images will be expanded to fit using the
background color. Use +append to stack images left-to-right.
The set of images is terminated by the appearance of any option.
If the -append option appears after all of the input images, all
images are appended.
-authenticate<string>
decrypt image with this password
Use this option to supply a password for decrypting an image or
an image sequence, if it is being read from a format such as PDF
that supports encryption. Encrypting images being written is
not supported.
-average
average a set of images
The set of images is terminated by the appearance of any option.
If the -average option appears after all of the input images,
all images are averaged.
-backdrop
display the image centered on a backdrop.
This backdrop covers the entire workstation screen and is useful
for hiding other X window activity while viewing the image. The
color of the backdrop is specified as the foreground color (X11
default is black). Refer to "X Resources", below, for details.
-background<color>
the background color
The color is specified using the format described under the
-fill option.
-blue-primary<x>,<y>
blue chromaticity primary point
-blur<radius>{x<sigma>}
blur the image with a Gaussian operator
Blur with the given radius and standard deviation (sigma).
-border<width>x<height>
surround the image with a border of color
See -geometry for details about the geometry specification.
-bordercolor<color>
the border color
The color is specified using the format described under the
-fill option.
-borderwidth<geometry>
the border width
-box<color>
set the color of the annotation bounding box
The color is specified using the format described under the
-fill option.
See -draw for further details.
-cache<threshold>
(This option has been replaced by the -limit option)
-channel<type>
the type of channel
Choose from: Red, Green, Blue, Opacity, Matte, Cyan, Magenta,
Yellow, or Black.
Use this option to extract a particular channel from the image.
Matte, for example, is useful for extracting the opacity values
from an image.
-charcoal<factor>
simulate a charcoal drawing
-chop<width>x<height>{+-}<x>{+-}<y>{%}
remove pixels from the interior of an image
Width and height give the number of columns and rows to remove,
and x and y are offsets that give the location of the leftmost
column and topmost row to remove.
The x offset normally specifies the leftmost column to remove.
If the -gravity option is present with NorthEast,East, or
SouthEast gravity, it gives the distance leftward from the right
edge of the image to the rightmost column to remove. Similarly,
the y offset normally specifies the topmost row to remove, but
if the -gravity option is present with SouthWest,South, or
SouthEast gravity, it specifies the distance upward from the
bottom edge of the image to the bottom row to remove.
The -chop option removes entire rows and columns, and moves the
remaining corner blocks leftward and upward to close the gaps.
-clip apply the clipping path, if one is present
If a clipping path is present, it will be applied to subsequent
operations.
For example, if you type the following command:
gm convert -clip -negate cockatoo.tif negated.tif
only the pixels within the clipping path are negated.
The -clip feature requires the XML library. If the XML library
is not present, the option is ignored.
-coalesce
merge a sequence of images
Each image N in the sequence after Image 0 is replaced with the
image created by flattening images 0 through N.
The set of images is terminated by the appearance of any option.
If the -coalesce option appears after all of the input images,
all images are coalesced.
-colorize<value>
colorize the image with the pen color
Specify the amount of colorization as a percentage. You can
apply separate colorization values to the red, green, and blue
channels of the image with a colorization value list delimited
with slashes (e.g. 0/0/50).
-colormap<type>
define the colormap type
Choose between shared or private.
This option only applies when the default X server visual is
PseudoColor or GRAYScale. Refer to -visual for more details. By
default, a shared colormap is allocated. The image shares colors
with other X clients. Some image colors could be approximated,
therefore your image may look very different than intended.
Choose Private and the image colors appear exactly as they are
defined. However, other clients may go technicolor when the
image colormap is installed.
-colors<value>
preferred number of colors in the image
The actual number of colors in the image may be less than your
request, but never more. Note, this is a color reduction option.
Images with less unique colors than specified with this option
will have any duplicate or unused colors removed. The ordering
of an existing color palette may be altered. When converting an
image from color to grayscale, convert the image to the gray
colorspace before reducing the number of colors since doing so
is most efficient. Refer to <a href="quantize.html">quantize for
more details.
Note, options -dither, -colorspace, and -treedepth affect the
color reduction algorithm.
-colorspace<value>
the type of colorspace
Choices are: CMYK, GRAY, HSL, HWB, OHTA, RGB, Transparent, XYZ,
YCbCr, YIQ, YPbPr, or YUV.
Color reduction, by default, takes place in the RGB color space.
Empirical evidence suggests that distances in color spaces such
as YUV or YIQ correspond to perceptual color differences more
closely than do distances in RGB space. These color spaces may
give better results when color reducing an image. Refer to
quantize for more details.
The Transparent color space behaves uniquely in that it
preserves the matte channel of the image if it exists.
The -colors or -monochrome option, or saving to a file format
which requires color reduction, is required for this option to
take effect.
-comment<string>
annotate an image with a comment
Use this option to assign a specific comment to the image, when
writing to an image format that supports comments. You can
include the image filename, type, width, height, or other image
attribute by embedding special format characters listed under
the -format option. The comment is not drawn on the image, but
is embedded in the image datastream via a "Comment" tag or
similar mechanism. If you want the comment to be visible on the
image itself, use the -draw option.
For example,
-comment "%m:%f %wx%h"
produces an image comment of MIFF:bird.miff512x480 for an image
titled bird.miff and whose width is 512 and height is 480.
If the first character of string is @, the image comment is read
from a file titled by the remaining characters in the string.
-compose<operator>
the type of image composition
The description of composition uses abstract terminology in
order to allow the the description to be more clear, while
avoiding constant values which are specific to a particular
build configuration. Each image pixel is represented by red,
green, and blue levels (which are equal for a gray pixel).
MaxRGB is the maximum integral value which may be stored in the
red, green, or blue channels of the image. Each image pixel may
also optionally (if the image matte channel is enabled) have an
associated level of opacity (ranging from opaque to
transparent), which may be used to determine the influence of
the pixel color when compositing the pixel with another image
pixel. If the image matte channel is disabled, then all pixels
in the image are treated as opaque. The color of an opaque
pixel is fully visible while the color of a transparent pixel
color is entirely absent (pixel color is ignored).
By definition, raster images have a rectangular shape. All image
rows are of equal length, and all image columns have the same
number of rows. By treating the opacity channel as a visual
"mask" the rectangular image may be given a "shape" by treating
the opacity channel as a cookie-cutter for the image. Pixels
within the shape are opaque, while pixels outside the shape are
transparent. Pixels on the boundary of the shape may be between
opaque and transparent in order to provide antialiasing
(visually smooth edges). The description of the composition
operators use this concept of image "shape" in order to make the
description of the operators easier to understand. While it is
convenient to describe the operators in terms of "shapes" they
are by no means limited to mask-style operations since they are
based on continuous floating-point mathematics rather than
simple boolean operations.
By default, the Over composite operator is used. The following
composite operators are available:
Over
In
Out
Atop
Xor
Plus
Minus
Add
Subtract
Difference
Multiply
Bumpmap
Copy
CopyRed
CopyGreen
CopyBlue
CopyOpacity
The behavior of each operator is described below.
Over
.in 20 The result will be the union of the two image
shapes, with opaque areas of change-image obscuring base-image in the region of overlap.
In
.in 20 The result is simply change-image cut by the shape
of base-image. None of the image data of base-image will
be in the result.
Out
.in 20 The resulting image is change-image with the shape
of base-image cut out.
Atop
.in 20 The result is the same shape as base-image, with
change-image obscuring base-image where the image shapes
overlap. Note this differs from over because the portion
of change-image outside base-image’s shape does not appear
in the result.
Xor
.in 20 The result is the image data from both change-image
and base-image that is outside the overlap region. The
overlap region will be blank.
Plus
.in 20 The result is just the sum of the image data.
Output values are cropped to MaxRGB (no overflow). This
operation is independent of the matte channels.
Minus
.in 20 The result of change-image - base-image, with
underflow cropped to zero. The matte channel is ignored
(set to opaque, full coverage).
Add
.in 20 The result of change-image + base-image, with
overflow wrapping around (mod MaxRGB+1).
Subtract
.in 20 The result of change-image - base-image, with
underflow wrapping around (mod MaxRGB+1). The add and
subtract operators can be used to perform reversible
transformations.
Difference
.in 20 The result of abs(change-image - base-image). This
is useful for comparing two very similar images.
Multiply
.in 20 The result of change-image * base-image. This is
useful for the creation of drop-shadows.
Bumpmap
.in 20 The result base-image shaded by change-image.
Copy
.in 20 The resulting image is base-image replaced with
change-image. Here the matte information is ignored.
CopyRed
.in 20 The resulting image is the red channel in base-image replaced with the red channel in change-image. The
other channels are copied untouched.
CopyGreen
.in 20 The resulting image is the green channel in base-image replaced with the green channel in change-image. The
other channels are copied untouched.
CopyBlue
.in 20 The resulting image is the blue channel in base-image replaced with the blue channel in change-image. The
other channels are copied untouched.
CopyOpacity
.in 20 The resulting image is the opacity channel in base-image replaced with the opacity channel in change-image.
The other channels are copied untouched.
-compress<type>
the type of image compression
Choices are: None, BZip, Fax, Group4, JPEG, Lossless, LZW, RLE
or Zip.
Specify +compress to store the binary image in an uncompressed
format. The default is the compression type of the specified
image file.
If LZW compression is specified but LZW compression has not been
enabled, the image data will be written in an uncompressed LZW
format that can be read by LZW decoders. This may result in
larger-than-expected GIF files.
"Lossless" refers to lossless JPEG, which is only available if
the JPEG library has been patched to support it. Use of lossless
JPEG is generally not recommended.
Use the -quality option to set the compression level to be used
by JPEG, PNG, MIFF, and MPEG encoders. Use the -sampling-factor
option to set the sampling factor to be used by JPEG, MPEG, and
YUV encoders for downsampling the chroma channels.
-contrast
enhance or reduce the image contrast
This option enhances the intensity differences between the
lighter and darker elements of the image. Use -contrast to
enhance the image or +contrast to reduce the image contrast.
For a more pronounced effect you can repeat the option:
gm convert rose: -contrast -contrast rose_c2.png
-convolve<kernel>
convolve image with the specified convolution kernel
The kernel is specified as a comma-separated list of integers,
ordered left-to right, starting with the top row. The order of
the kernel is determined by the square root of the number of
entries. Presently only square kernels are supported.
-crop<width>x<height>{+-}<x>{+-}<y>{%}
preferred size and location of the cropped image
See -geometry for details about the geometry specification.
The width and height give the size of the image that remains
after cropping, and x and y are offsets that give the location
of the top left corner of the cropped image with respect to the
original image. To specify the amount to be removed, use -shave
instead.
If the x and y offsets are present, a single image is generated,
consisting of the pixels from the cropping region. The offsets
specify the location of the upper left corner of the cropping
region measured downward and rightward with respect to the upper
left corner of the image. If the -gravity option is present
with NorthEast,East, or SouthEast gravity, it gives the
distance leftward from the right edge of the image to the right
edge of the cropping region. Similarly, if the -gravity option
is present with SouthWest,South, or SouthEast gravity, the
distance is measured upward between the bottom edges.
If the x and y offsets are omitted, a set of tiles of the
specified geometry, covering the entire input image, is
generated. The rightmost tiles and the bottom tiles are smaller
if the specified geometry extends beyond the dimensions of the
input image.
-cycle<amount>
displace image colormap by amount
Amount defines the number of positions each colormap entry
isshifted.
-debug<events>
enable debug printout
The events parameter specifies which events are to be logged.
It can be either None, All, or a comma-separated list consisting
of one or more of the following domains: Annotate, Blob, Cache,
Coder, Configure, Deprecate, Error, Exception, Locale,
Render,Resource, TemporaryFile, Transform, Warning, X11, or
User. For example, to log cache and blob events, use
gm convert -debug "Cache,Blob" rose: rose.png
The "User" domain is normally empty, but developers can log
"User" events in their private copy of GraphicsMagick.
Use the -log option to specify the format for debugging output.
Use +debug to turn off all logging.
An alternative to using -debug is to use the MAGICK_DEBUG
environment variable. The allowed values for the MAGICK_DEBUG
environment variable are the same as for the -debug option.
-deconstruct
break down an image sequence into constituent parts
This option compares each image with the next in a sequence and
returns the maximum bounding region of any pixel differences it
discovers. This method can undo a coalesced sequence returned
by the -coalesce option, and is useful for removing redundant
information from a GIF or MNG animation.
The sequence of images is terminated by the appearance of any
option. If the -deconstruct option appears after all of the
input images, all images are deconstructed.
-define<key>{=<value>},...
add coder/decoder specific options This option creates one or
more definitions for coders and decoders to use while reading
and writing image data. Definitions may be passed to coders and
decoders to control options that are specific to certain image
formats. If value is missing for a definition, an empty-valued
definition of a flag will be created with that name. This is
used to control on/off options. Use +define <key>,... to remove
definitions previously created. Use +define "*" to remove all
existing definitions.
The following definitions may be created:
jp2:rate=<value>
.in 20
Specify the compression factor to use while writing
JPEG-2000 files. The compression factor is the reciprocal
of the compression ratio. The valid range is 0.0 to 1.0,
with 1.0 indicating lossless compression. If defined, this
value overrides the -quality setting. The default quality
setting of 75 results in a rate value of 0.06641.
jpeg:preserve-settings
.in 20
If the jpeg:preserve-settings flag is defined, the JPEG
encoder will use the same "quality" and "sampling-factor"
settings that were found in the input file, if the input
was in JPEG format. These settings are also preserved if
the input is a JPEG file and the output is a JNG file. If
the colorspace of the output file differs from that of the
input file, the quality setting is preserved but the
sampling-factors are not.
ps:imagemask
.in 20
If the ps:imagemask flag is defined, the PS3 and EPS3
coders will create Postscript files that render bilevel
images with the Postscript imagemask operator instead of
the image operator.
tiff:bits-per-sample=<value>
.in 20
If the tiff:bits-per-sample key is defined to a value less
than the GraphicsMagick Quantum depth, the TIFF coder will
write TIFF images with the defined bits per sample,
overriding any value stored in the image.
tiff:fill-order={msb2lsb|lsb2msb}
.in 20 If the tiff:fill-order key is defined,
GraphicsMagick will use it to determine the bit fill order
used while writing TIFF files. The normal default is
"msb2lsb", which matches the native bit order of all
modern CPUs. The only exception to this is when Group3 or
Group4 FAX compression is requested since FAX machines
send data in bit-reversed order and therefore RFC 2301
recommends using reverse order.
tiff:samples-per-pixel=<value>
.in 20
If the tiff:samples-per-pixel key is defined to a value,
the TIFF coder will write TIFF images with the defined
samples per pixel, overriding any value stored in the
image.
For example, to create a postscript file that will render only
the black pixels of a bilevel image, use:
gm convert bilevel.tif -define ps:imagemask eps3:stencil.ps
-delay<1/100thsofasecond>
display the next image after pausing
This option is useful for regulating the animation of image
sequences Delay/100 seconds must expire before the display of
the next image. The default is no delay between each showing of
the image sequence. The maximum delay is 65535.
You can specify a delay range (e.g. -delay10-500) which sets
the minimum and maximum delay.
-density<width>x<height>
horizontal and vertical resolution in pixels of the image This
option specifies the image resolution to store while encoding a
raster image or the canvas resolution while rendering (reading)
vector formats such as Postscript, PDF, WMF, and SVG into a
raster image. Image resolution provides the unit of measure to
apply when rendering to an output device or raster image. The
default unit of measure is in dots per inch (DPI). The -units
option may be used to select dots per centimeter instead.
The default resolution is 72 dots per inch, which is equivalent
to one point per pixel (Macintosh and Postscript standard).
Computer screens are normally 72 or 96 dots per inch while
printers typically support 150, 300, 600, or 1200 dots per inch.
To determine the resolution of your display, use a ruler to
measure the width of your screen in inches, and divide by the
number of horizontal pixels (1024 on a 1024x768 display). If
the file format supports it, this option may be used to update
the stored image resolution. Note that Photoshop stores and
obtains image resolution from a proprietary embedded profile. If
this profile is not stripped from the image, then Photoshop will
continue to treat the image using its former resolution,
ignoring the image resolution specified in the standard file
header. The density option is an attribute and does not alter
the underlying raster image. It may be used to adjust the
rendered size for desktop publishing purposes by adjusting the
scale applied to the pixels. To resize the image so that it is
the same size at a different resolution, use the -resample
option.
-depth<value>
depth of the image
This is the number of bits in a color sample within a pixel. The
only acceptable values are 8 or 16. Use this option to specify
the depth of raw images whose depth is unknown such as GRAY,
RGB, or CMYK, or to change the depth of any image after it has
been read.
-descend
obtain image by descending window hierarchy
-despeckle
reduce the speckles within an image
-displace<horizontalscale>x<verticalscale>
shift image pixels as defined by a displacement map
With this option, compositeimage is used as a displacement map.
Black, within the displacement map, is a maximum positive
displacement. White is a maximum negative displacement and
middle gray is neutral. The displacement is scaled to determine
the pixel shift. By default, the displacement applies in both
the horizontal and vertical directions. However, if you specify
mask, compositeimage is the horizontal X displacement and mask
the vertical Y displacement.
-display<host:display[.screen]>
specifies the X server to contact
This option is used with convert for obtaining image or font
from this X server. See X(1).
-dispose<method>
GIF disposal method
The Disposal Method indicates the way in which the graphic is to
be treated after being displayed.
Here are the valid methods:
Undefined No disposal specified.
None Do not dispose between frames.
Background Overwrite the image area with
the background color.
Previous Overwrite the image area with
what was there prior to rendering
the image.
-dissolve<percent>
dissolve an image into another by the given percent
The opacity of the composite image is multiplied by the given
percent, then it is composited over the main image.
-dither
apply Floyd/Steinberg error diffusion to the image
The basic strategy of dithering is to trade intensity resolution
for spatial resolution by averaging the intensities of several
neighboring pixels. Images which suffer from severe contouring
when reducing colors can be improved with this option.
The -colors or -monochrome option is required for this option to
take effect.
Use +dither to turn off dithering and to render PostScript
without text or graphic aliasing. Disabling dithering often (but
not always) leads to decreased processing time.
-draw<string>
annotate an image with one or more graphic primitives
Use this option to annotate an image with one or more graphic
primitives. The primitives include shapes, text,
transformations, and pixel operations. The shape primitives are
point x,y
line x0,y0 x1,y1
rectangle x0,y0 x1,y1
roundRectangle x0,y0 x1,y1 wc,hc
arc x0,y0 x1,y1 a0,a1
ellipse x0,y0 rx,ry a0,a1
circle x0,y0 x1,y1
polyline x0,y0 ... xn,yn
polygon x0,y0 ... xn,yn
Bezier x0,y0 ... xn,yn
path path specification
image operator x0,y0 w,h filename
The text primitive is
text x0,y0 string
The text gravity primitive is
gravity NorthWest, North, NorthEast, West, Center,
East, SouthWest, South, or SouthEast
The text gravity primitive only affects the placement of text
and does not interact with the other primitives. It is
equivalent to using the -gravity commandline option, except that
it is limited in scope to the -draw option in which it appears.
The transformation primitives are
rotate degrees
translate dx,dy
scale sx,sy
skewX degrees
skewY degrees
The pixel operation primitives are
color x0,y0 method
matte x0,y0 method
The shape primitives are drawn in the color specified in the
preceding -stroke option. Except for the line and point
primitives, they are filled with the color specified in the
preceding -fill option. For unfilled shapes, use -fill none.
Point requires a single coordinate.
Line requires a start and end coordinate.
Rectangle expects an upper left and lower right coordinate.
RoundRectangle has the upper left and lower right coordinates
and the width and height of the corners.
Circle has a center coordinate and a coordinate for the outer
edge.
Use Arc to inscribe an elliptical arc within a rectangle. Arcs
require a start and end point as well as the degree of rotation
(e.g. 130,30 200,100 45,90).
Use Ellipse to draw a partial ellipse centered at the given
point with the x-axis and y-axis radius and start and end of arc
in degrees (e.g. 100,100 100,150 0,360).
Finally, polyline and polygon require three or more coordinates
to define its boundaries. Coordinates are integers separated by
an optional comma. For example, to define a circle centered at
100,100 that extends to 150,150 use:
-draw ’circle 100,100 150,150’
Paths (See Paths) represent an outline of an object which is
defined in terms of moveto (set a new current point), lineto
(draw a straight line), curveto (draw a curve using a cubic
Bezier), arc (elliptical or circular arc) and closepath (close
the current shape by drawing a line to the last moveto)
elements. Compound paths (i.e., a path with subpaths, each
consisting of a single moveto followed by one or more line or
curve operations) are possible to allow effects such as "donut
holes" in objects.
Use image to composite an image with another image. Follow the
image keyword with the composite operator, image location, image
size, and filename:
-draw ’image Over 100,100 225,225 image.jpg’
You can use 0,0 for the image size, which means to use the
actual dimensions found in the image header. Otherwise, it will
be scaled to the given dimensions. See -compose for a
description of the composite operators.
Use text to annotate an image with text. Follow the text
coordinates with a string. If the string has embedded spaces,
enclose it in single or double quotes. Optionally you can
include the image filename, type, width, height, or other image
attribute by embedding special format character. See -comment
for details.
For example,
-draw ’text 100,100 "%m:%f %wx%h"’
annotates the image with MIFF:bird.miff 512x480 for an image
titled bird.miff and whose width is 512 and height is 480.
If the first character of string is @, the text is read from a
file titled by the remaining characters in the string.
Rotate rotates subsequent shape primitives and text primitives
about the origin of the main image. If the -region option
precedes the -draw option, the origin for transformations is the
upper left corner of the region.
Translate translates them.
Scale scales them.
SkewX and SkewY skew them with respect to the origin of the main
image or the region.
The transformations modify the current affine matrix, which is
initialized from the initial affine matrix defined by the
-affine option. Transformations are cumulative within the -draw
option. The initial affine matrix is not affected; that matrix
is only changed by the appearance of another -affine option. If
another -draw option appears, the current affine matrix is
reinitialized from the initial affine matrix.
Use color to change the color of a pixel to the fill color (see
-fill). Follow the pixel coordinate with a method:
point
replace
floodfill
filltoborder
reset
Consider the target pixel as that specified by your coordinate.
The point method recolors the target pixel. The replace method
recolors any pixel that matches the color of the target pixel.
Floodfill recolors any pixel that matches the color of the
target pixel and is a neighbor, whereas filltoborder recolors
any neighbor pixel that is not the border color. Finally, reset
recolors all pixels.
Use matte to the change the pixel matte value to transparent.
Follow the pixel coordinate with a method (see the color
primitive for a description of methods). The point method
changes the matte value of the target pixel. The replace method
changes the matte value of any pixel that matches the color of
the target pixel. Floodfill changes the matte value of any pixel
that matches the color of the target pixel and is a neighbor,
whereas filltoborder changes the matte value of any neighbor
pixel that is not the border color (-bordercolor). Finally
reset changes the matte value of all pixels.
You can set the primitive color, font, and font bounding box
color with -fill, -font, and -box respectively. Options are
processed in command line order so be sure to use these options
before the -draw option.
-edge<radius>
detect edges within an image
-emboss<radius>
emboss an image
-encoding<type>
specify the text encoding
Choose from AdobeCustom,AdobeExpert,AdobeStandard,AppleRoman,BIG5,GB2312,Latin2,None,SJIScode,Symbol,Unicode,Wansung.-endian<type>
specify endianness (MSB or LSB) of output image
Use +endian to revert to unspecified endianness.
-enhance
apply a digital filter to enhance a noisy image
-equalize
perform histogram equalization to the image
-fill<color>
color to use when filling a graphic primitive
Colors are represented in GraphicsMagick in the same form used
by SVG. Use "gm convert -list color" to list named colors:
name (named color)
#RGB (hex numbers, 4 bits each)
#RRGGBB (8 bits each)
#RRRGGGBBB (12 bits each)
#RRRRGGGGBBBB (16 bits each)
#RGBA (4 bits each)
#RRGGBBAA (8 bits each)
#RRRGGGBBBAAA (12 bits each)
#RRRRGGGGBBBBAAAA (16 bits each)
rgb(r,g,b) (r,g,b are decimal numbers)
rgba(r,g,b,a) (r,g,b,a are decimal numbers)
Enclose the color specification in quotation marks to prevent
the "#" or the parentheses from being interpreted by your shell.
For example,
gm convert -fill blue ...
gm convert -fill "#ddddff" ...
gm convert -fill "rgb(65000,65000,65535)" ...
The shorter forms are scaled up, if necessary by replication.
For example, #3af, #33aaff, and #3333aaaaffff are all
equivalent.
See -draw for further details.
-filter<type>
use this type of filter when resizing an image
Use this option to affect the resizing operation of an image
(see -geometry). Choose from these filters:
Point
Box
Triangle
Hermite
Hanning
Hamming
Blackman
Gaussian
Quadratic
Cubic
Catrom
Mitchell
Lanczos
Bessel
Sinc
The default filter is automatically selected to provide the best
quality while consuming a reasonable amount of time. The
Mitchell filter is used if the image supports a palette,
supports a matte channel, or is being enlarged, otherwise the
Lanczos filter is used.
-flatten
flatten a sequence of images
The sequence of images is replaced by a single image created by
composing each image after the first over the first image.
The sequence of images is terminated by the appearance of any
option. If the -flatten option appears after all of the input
images, all images are flattened.
-flip create a "mirror image"
reflect the scanlines in the vertical direction.
-flop create a "mirror image"
reflect the scanlines in the horizontal direction.
-font<name>
use this font when annotating the image with text
You can tag a font to specify whether it is a PostScript,
TrueType, or OPTION1 font. For example, Arial.ttf is a TrueType
font, ps:helvetica is PostScript, and x:fixed is OPTION1.
-foreground<color>
define the foreground color
The color is specified using the format described under the
-fill option.
-format<type>
the image format type
When used with the mogrify utility, this option will convert any
image to the image format you specify. See GraphicsMagick(1)
for a list of image format types supported by GraphicsMagick, or
see the output of ’gm -list format’.
By default the file is written to its original name. However,
if the filename extension matches a supported format, the
extension is replaced with the image format type specified with
-format. For example, if you specify tiff as the format type
and the input image filename is image.gif, the output image
filename becomes image.tiff.
-format<string>
output formatted image characteristics
When used with the identify utility, use this option to print
information about the image in a format of your choosing. You
can include the image filename, type, width, height, Exif data,
or other image attributes by embedding special format
characters:
%b file size
%c comment
%d directory
%e filename extension
%f filename
%h height
%i input filename
%k number of unique colors
%l label
%m magick
%n number of scenes
%o output filename
%p page number
%q quantum depth
%s scene number
%t top of filename
%u unique temporary filename
%w width
%x x resolution
%y y resolution
%# signature
\n newline
\r carriage return
For example,
-format "%m:%f %wx%h"
displays MIFF:bird.miff512x480 for an image titled bird.miff
and whose width is 512 and height is 480.
If the first character of string is @, the format is read from a
file titled by the remaining characters in the string.
You can also use the following special formatting syntax to
print Exif information contained in the file:
%[EXIF:<tag>]
Where "<tag>" can be one of the following:
* (print all Exif tags, in keyword=data format)
! (print all Exif tags, in tag_number data format)
#hhhh (print data for Exif tag #hhhh)
ImageWidth
ImageLength
BitsPerSample
Compression
PhotometricInterpretation
FillOrder
DocumentName
ImageDescription
Make
Model
StripOffsets
Orientation
SamplesPerPixel
RowsPerStrip
StripByteCounts
XResolution
YResolution
PlanarConfiguration
ResolutionUnit
TransferFunction
Software
DateTime
Artist
WhitePoint
PrimaryChromaticities
TransferRange
JPEGProc
JPEGInterchangeFormat
JPEGInterchangeFormatLength
YCbCrCoefficients
YCbCrSubSampling
YCbCrPositioning
ReferenceBlackWhite
CFARepeatPatternDim
CFAPattern
BatteryLevel
Copyright
ExposureTime
FNumber
IPTC/NAA
ExifOffset
InterColorProfile
ExposureProgram
SpectralSensitivity
GPSInfo
ISOSpeedRatings
OECF
ExifVersion
DateTimeOriginal
DateTimeDigitized
ComponentsConfiguration
CompressedBitsPerPixel
ShutterSpeedValue
ApertureValue
BrightnessValue
ExposureBiasValue
MaxApertureValue
SubjectDistance
MeteringMode
LightSource
Flash
FocalLength
MakerNote
UserComment
SubSecTime
SubSecTimeOriginal
SubSecTimeDigitized
FlashPixVersion
ColorSpace
ExifImageWidth
ExifImageLength
InteroperabilityOffset
FlashEnergy
SpatialFrequencyResponse
FocalPlaneXResolution
FocalPlaneYResolution
FocalPlaneResolutionUnit
SubjectLocation
ExposureIndex
SensingMethod
FileSource
SceneType
Surround the format specification with quotation marks to
prevent your shell from misinterpreting any spaces and square
brackets.
-frame<width>x<height>+<outerbevelwidth>+<innerbevelwidth>
surround the image with an ornamental border
See -geometry for details about the geometry specification. The
-frame option is not affected by the -gravity option.
The color of the border is specified with the -mattecolor
command line option.
-frame include the X window frame in the imported image
-fuzz<distance>{%}
colors within this distance are considered equal
A number of algorithms search for a target color. By default the
color must be exact. Use this option to match colors that are
close to the target color in RGB space. For example, if you want
to automatically trim the edges of an image with -trim but the
image was scanned and the target background color may differ by
a small amount. This option can account for these differences.
The distance can be in absolute intensity units or, by appending
"%", as a percentage of the maximum possible intensity (255,
65535, or 4294967295).
-gamma<value>
level of gamma correction
The same color image displayed on two different workstations may
look different due to differences in the display monitor. Use
gamma correction to adjust for this color difference. Reasonable
values extend from 0.8 to 2.3. Gamma less than 1.0 darkens the
image and gamma greater than 1.0 lightens it. Large adjustments
to image gamma may result in the loss of some image information
if the pixel quantum size is only eight bits (quantum range 0 to
255).
You can apply separate gamma values to the red, green, and blue
channels of the image with a gamma value list delimited with
slashes (e.g., 1.7/2.3/1.2).
Use +gammavalue to set the image gamma level without actually
adjusting the image pixels. This option is useful if the image
is of a known gamma but not set as an image attribute (e.g. PNG
images).
-Gaussian<radius>{x<sigma>}
blur the image with a Gaussian operator
Use the given radius and standard deviation (sigma).
-geometry<width>x<height>{+-}<x>{+-}<y>{%}{@}{!}{<}{>}
preferred size and location of the Image window.
By default, the window size is the image size and the location
is chosen by you when it is mapped.
By default, the width and height are maximum values. That is,
the image is expanded or contracted to fit the width and height
value while maintaining the aspect ratio of the image. Appendanexclamationpointtothegeometrytoforcetheimagesizetoexactlythesizeyouspecify. For example, if you specify
640x480! the image width is set to 640 pixels and height to 480.
If only the width is specified, the width assumes the value and
the height is chosen to maintain the aspect ratio of the image.
Similarly, if only the height is specified (e.g., -geometry
x256), the width is chosen to maintain the aspect ratio.
To specify a percentage width or height instead, append %. The
image size is multiplied by the width and height percentages to
obtain the final image dimensions. To increase the size of an
image, use a value greater than 100 (e.g. 125%). To decrease an
image’s size, use a percentage less than 100.
Use @ to specify the maximum area in pixels of an image.
Use > to change the dimensions of the image only if its width or
height exceeds the geometry specification. < resizes the image
only if both of its dimensions are less than the geometry
specification. For example, if you specify ’640x480>’ and the
image size is 256x256, the image size does not change. However,
if the image is 512x512 or 1024x1024, it is resized to 480x480.
Enclose the geometry specification in quotation marks to prevent
the < or > from being interpreted by your shell as a file
redirection.
When used with animate and display, offsets are handled in the
same manner as in X(1) and the -gravity option is not used. If
the x is negative, the offset is measured leftward from the
right edge of the screen to the right edge of the image being
displayed. Similarly, negative y is measured between the bottom
edges. The offsets are not affected by "%"; they are always
measured in pixels.
When used as a composite option, -geometry gives the dimensions
of the image and its location with respect to the composite
image. If the -gravity option is present with NorthEast,East,
or SouthEast gravity, the x represents the distance from the
right edge of the image to the right edge of the composite
image. Similarly, if the -gravity option is present with
SouthWest,South, or SouthEast gravity, y is measured between
the bottom edges. Accordingly, a positive offset will never
point in the direction outside of the image. The offsets are
not affected by "%"; they are always measured in pixels. To
specify the dimensions of the composite image, use the -resize
option.
When used as a convert, import or mogrify option, -geometry is
synonymous with -resize and specifies the size of the output
image. The offsets, if present, are ignored.
When used as a montage option, -geometry specifies the image
size and border size for each tile; default is 256x256+0+0.
Negative offsets (border dimensions) are meaningless. The
-gravity option affects the placement of the image within the
tile; the default gravity for this purpose is Center. If the
"%" sign appears in the geometry specification, the tile size is
the specified percentage of the original dimensions of the first
tile. To specify the dimensions of the montage, use the -resize
option.
-gravity<type>
direction primitive gravitates to when annotating the image.
Choices are: NorthWest, North, NorthEast, West, Center, East,
SouthWest, South, SouthEast.
The direction you choose specifies where to position the text
when annotating the image. For example Center gravity forces the
text to be centered within the image. By default, the image
gravity is NorthWest. See -draw for more details about graphic
primitives. Only the text primitive is affected by the -gravity
option.
The -gravity option is also used in concert with the -geometry
option and other options that take <geometry> as a parameter,
such as the -crop option. See -geometry for details of how the
-gravity option interacts with the <x> and <y> parameters of a
geometry specification.
When used as an option to composite, -gravity gives the
direction that the image gravitates within the composite.
When used as an option to montage, -gravity gives the direction
that an image gravitates within a tile. The default gravity is
Center for this purpose.
-green-primary<x>,<y>
green chromaticity primary point
-help print usage instructions
-iconGeometry<geometry>
specify the icon geometry
Offsets, if present in the geometry specification, are handled
in the same manner as the -geometry option, using X11 style to
handle negative offsets.
-iconic
iconic animation
-immutable
make image immutable
-implode<factor>
implode image pixels about the center
-intent<type>
use this type of rendering intent when managing the image color
Use this option to affect the the color management operation of
an image (see -profile). Choose from these intents: Absolute,Perceptual,Relative,Saturation.
The default intent is undefined.
-interlace<type>
the type of interlacing scheme
Choices are: None,Line,Plane, or Partition. The default is
None.
This option is used to specify the type of interlacing scheme
for raw image formats such as RGB or YUV. None means do not
interlace (RGBRGBRGBRGBRGBRGB...),
Line uses scanline interlacing
(RRR...GGG...BBB...RRR...GGG...BBB...), and Plane uses plane
interlacing (RRRRRR...GGGGGG...BBBBBB...).
Partition is like plane except the different planes are saved to
individual files (e.g. image.R, image.G, and image.B).
Use Line or Plane to create an interlacedPNG or GIF or
progressiveJPEG image.
-label<name>
assign a label to an image
Use this option to assign a specific label to the image, when
writing to an image format that supports labels, such as TIFF,
PNG, MIFF, or PostScript. You can include the the image
filename, type, width, height, or other image attribute by
embedding special format character. A label is not drawn on the
image, but is embedded in the image datastream via a "Label" tag
or similar mechanism. If you want the label to be visible on
the image itself, use the -draw option. See -comment for
details.
For example,
-label "%m:%f %wx%h"
produces an image label of MIFF:bird.miff512x480 for an image
titled bird.miff and whose width is 512 and height is 480.
If the first character of string is @, the image label is read
from a file titled by the remaining characters in the string.
When converting to PostScript, use this option to specify a
header string to print above the image. Specify the label font
with -font.
When creating a montage, by default the label associated with an
image is displayed with the corresponding tile in the montage.
Use the +label option to suppress this behavior.
-lat<width>x<height>{+-}<offset>{%}
perform local adaptive thresholding
Perform local adaptive thresholding using the specified width,
height, and offset. The offset is a distance in sample space
from the mean, as an absolute integer ranging from 0 to the
maximum sample value or as a percentage.
-level<black_point>{,<gamma>}{,<white_point>}{%}
adjust the level of image contrast
Give one, two or three values delimited with commas: black-
point, gamma, white-point (e.g. 10,1.0,250 or 2%,0.5,98%). The
black and white points range from 0 to MaxRGB or from 0 to 100%;
if the white point is omitted it is set to MaxRGB-black_point.
If a "%" sign is present anywhere in the string, the black and
white points are percentages of MaxRGB. Gamma is an exponent
that ranges from 0.1 to 10.; if it is omitted, the default of
1.0 (no gamma correction) is assumed. This interface works
similar to Photoshop’s "Image->Adjustments->Levels..." "Input
Levels" interface.
-limit<type><value>
Disk, File, Map, or Memory resource limit
The value for File is in number of files and the values for the
other resources are in Megabytes. By default the limits are 256
files, 1024MB memory, 4096MB map, and unlimited disk, but these
are adjusted at startup time on platforms that can provide
information about available resources. When the limit is
reached, GraphicsMagick will fail in some fashion, or take
compensating actions if possible. For example, -limit memory 32
-limit map 64 limits memory When the pixel cache reaches the
memory limit it uses memory mapping. When that limit is reached
it goes to disk. If disk has a hard limit, the program will
fail.
Resource limits may also be set using environment variables. The
environment variables MAGICK_LIMIT_DISK, MAGICK_LIMIT_FILES,
MAGICK_LIMIT_MEMORY, and MAGICK_LIMIT_MAP, may be used to set
the limits for disk space, open files, heap memory, and memory
map size, respectively.
You can use the option -list resource to find out the limits.
-linewidth
the line width for subsequent draw operations
-list<type>
the type of list
Choices are: Color, Delegate, Format, Magic, Module, Resource,
or Type. The Module option is only available if GraphicsMagick
was built to support loadable modules.
This option lists information about the GraphicsMagick
configuration.
-log<string>
Specify format for debug log
This option specifies the format for the log printed when the
-debug option is active.
You can display the following components by embedding special
format characters:
%d domain
%e event
%f function
%l line
%m module
%p process ID
%r real CPU time
%t wall clock time
%u user CPU time
%% percent sign
\n newline
\r carriage return
For example:
gm convert -debug coders -log "%u %m:%l %e" in.gif out.png
The default behavior is to print all of the components.
-loop<iterations>
add Netscape loop extension to your GIF animation
A value other than zero forces the animation to repeat itself up
to iterations times.
-magnify<factor>
magnify the image
-map<filename>
choose a particular set of colors from this image
[convert or mogrify]
By default, color reduction chooses an optimal set of colors
that best represent the original image. Alternatively, you can
choose a particular set of colors from an image file with this
option.
Use +map to reduce all images in the image sequence that follows
to a single optimal set of colors that best represent all the
images. The sequence of images is terminated by the appearance
of any option. If the +map option appears after all of the
input images, all images are mapped.
-map<type>
display image using this type.
[animate or display]
Choose from these StandardColormap types:
best
default
gray
red
green
blue
The Xserver must support the StandardColormap you choose,
otherwise an error occurs. Use list as the type and display
searches the list of colormap types in top-to-bottom order until
one is located. See xstdcmap(1) for one way of creating Standard
Colormaps.
-mask<filename>
Specify a clipping mask
The image read from the file is used as a clipping mask. It
must have the same dimensions as the image being masked.
If the mask image contains an opacity channel, the opacity of
each pixel is used to define the mask. Otherwise, the intensity
(gray level) of each pixel is used.
Use +mask to remove the clipping mask.
It is not necessary to use -clip to activate the mask; -clip is
implied by -mask.
-matte store matte channel if the image has one
If the image does not have a matte channel, create an opaque
one.
Use +matte to ignore the matte channel and to avoid writing a
matte channel in the output file.
-mattecolor<color>
specify the color to be used with the -frame option
The color is specified using the format described under the
-fill option.
-median<radius>
apply a median filter to the image
-mode<value>
mode of operation
-modulatebrightness[,saturation[,hue]]
vary the brightness, saturation, and hue of an image
Specify the percent change in brightness, color saturation, and
hue separated by commas. Default argument values are 100
percent, resulting in no change. For example, to increase the
color brightness by 20% and decrease the color saturation by 10%
and leave the hue unchanged, use: -modulate120,90.
Hue is the percentage of absolute rotation from the current
position. For example 50 results in a counter-clockwise rotation
of 90 degrees, 150 results in a clockwise rotation of 90
degrees, with 0 and 200 both resulting in a rotation of 180
degrees.
-monochrome
transform the image to black and white
-morph<frames>
morphs an image sequence
Both the image pixels and size are linearly interpolated to give
the appearance of a meta-morphosis from one image to the next.
The sequence of images is terminated by the appearance of any
option. If the -morph option appears after all of the input
images, all images are morphed.
-mosaic
create a mosaic from an image or an image sequence
The -page option can be used to establish the dimensions of the
mosaic and to locate the images within the mosaic.
The sequence of images is terminated by the appearance of any
option. If the -mosaic option appears after all of the input
images, all images are included in the mosaic.
-name name an image
-negate
replace every pixel with its complementary color
The red, green, and blue intensities of an image are negated.
White becomes black, yellow becomes blue, etc. Use +negate to
only negate the grayscale pixels of the image.
-noise<radius|type>
add or reduce noise in an image
The principal function of noise peak elimination filter is to
smooth the objects within an image without losing edge
information and without creating undesired structures. The
central idea of the algorithm is to replace a pixel with its
next neighbor in value within a pixel window, if this pixel has
been found to be noise. A pixel is defined as noise if and only
if this pixel is a maximum or minimum within the pixel window.
Use radius to specify the width of the neighborhood.
Use +noise followed by a noise type to add noise to an image.
Choose from these noise types:
Uniform
Gaussian
Multiplicative
Impulse
Laplacian
Poisson
-noop NOOP (no option)
The -noop option can be used to terminate a group of images and
reset all options to their default values, when no other option
is desired.
-normalize
transform image to span the full range of color values
This is a contrast enhancement technique.
-opaque<color>
change this color to the pen color within the image
The color is specified using the format described under the
-fill option.
See -fill for more details.
-operatorchanneloperatorrvalue[%]
apply a mathematical or bitwise operator to an image channel
Apply a low-level mathematical or bitwise operator to a selected
image channel or all image channels. Operations which result in
negative results are reset to zero, and operations which
overflow the available range are reset to the maximum possible
value.
Select a channel from: Red, Green, Blue, Opacity, Matte, Cyan,
Magenta, Yellow, Black, or All.
Select an operator from Add, And, Divide, LShift, Multiply, Or,
RShift, Subtract, Xor.
Rvalue may be any floating point value in the range of 0 to
MaxRGB, where MaxRGB is the largest quantum value supported by
the GraphicsMagick build (255, 65535, or 4294967295). If a
percent (%) symbol is appended to the argument, then the
argument has a range of 0 to 100 percent.
-ordered-dither<channeltype><NxN>
ordered dither the image
The channel or channels specified in the channeltype argument
are reduced to binary, using an ordered dither method. The
choices for channeltype are:
all
intensity
opacity
matte
When channeltype is "all", the color samples are dithered into a
graylevel and then that graylevel is stored in the three color
channels. Separately, the opacity channel is dithered into a
bilevel opacity value which is stored in the opacity channel.
When channeltype is "intensity", only the color samples are
dithered. When channeltype is "opacity" or "matte", only the
opacity channel is dithered.
The choices for N are 2, 3, or 4. When N is 2, the image is
divided into 2x2 pixel tiles. In each tile, 0, 1, 2, 3, or 4
pixels are turned to white depending on their intensity. When N
is 3, there are 3x3 tiles and 10 levels of gray can be
represented. When N is 4, there are 4x4 tiles and 17 levels of
gray.
-page<width>x<height>{+-}<x>{+-}<y>{%}{!}{<}{>}
size and location of an image canvas
Use this option to specify the dimensions of the PostScript page
in dots per inch or a TEXT page in pixels. The choices for a
PostScript page are:
11x17 792 1224
Ledger 1224 792
Legal 612 1008
Letter 612 792
LetterSmall 612 792
ArchE 2592 3456
ArchD 1728 2592
ArchC 1296 1728
ArchB 864 1296
ArchA 648 864
A0 2380 3368
A1 1684 2380
A2 1190 1684
A3 842 1190
A4 595 842
A4Small 595 842
A5 421 595
A6 297 421
A7 210 297
A8 148 210
A9 105 148
A10 74 105
B0 2836 4008
B1 2004 2836
B2 1418 2004
B3 1002 1418
B4 709 1002
B5 501 709
C0 2600 3677
C1 1837 2600
C2 1298 1837
C3 918 1298
C4 649 918
C5 459 649
C6 323 459
Flsa 612 936
Flse 612 936
HalfLetter 396 612
For convenience you can specify the page size by media (e.g. A4,
Ledger, etc.). Otherwise, -page behaves much like -geometry
(e.g. -page letter+43+43>).
This option is also used to place subimages when writing to a
multi-image format that supports offsets, such as GIF89 and MNG.
When used for this purpose the offsets are always measured from
the top left corner of the canvas and are not affected by the
-gravity option. To position a GIF or MNG image, use
-page{+-}<x>{+-}<y> (e.g. -page +100+200). When writing to a
MNG file, a -page option appearing ahead of the first image in
the sequence with nonzero width and height defines the width and
height values that are written in the MHDR chunk. Otherwise,
the MNG width and height are computed from the bounding box that
contains all images in the sequence. When writing a GIF89 file,
only the bounding box method is used to determine its
dimensions.
For a PostScript page, the image is sized as in -geometry and
positioned relative to the lower left hand corner of the page by
{+-}<xoffset>{+-}<yoffset>. Use -page 612x792>, for example, to
center the image within the page. If the image size exceeds the
PostScript page, it is reduced to fit the page. The default
gravity for the -page option is NorthWest, i.e., positive x and
yoffset are measured rightward and downward from the top left
corner of the page, unless the -gravity option is present with a
value other than NorthWest.
The default page dimensions for a TEXT image is 612x792.
This option is used in concert with -density.
Use +page to remove the page settings for an image.
-paint<radius>
simulate an oil painting
Each pixel is replaced by the most frequent color in a circular
neighborhood whose width is specified with radius.
-pause<seconds>
pause between animation loops [animate]
Pause for the specified number of seconds before repeating the
animation.
-pause<seconds>
pause between snapshots [import]
Pause for the specified number of seconds before taking the next
snapshot.
-pen<color>
(This option has been replaced by the -fill option)
-ping efficiently determine image characteristics
-pointsize<value>
pointsize of the PostScript, OPTION1, or TrueType font
-preview<type>
image preview type
Use this option to affect the preview operation of an image
(e.g. convert file.png -preview Gamma Preview:gamma.png).
Choose from these previews:
Rotate
Shear
Roll
Hue
Saturation
Brightness
Gamma
Spiff
Dull
Grayscale
Quantize
Despeckle
ReduceNoise
Add Noise
Sharpen
Blur
Threshold
EdgeDetect
Spread
Shade
Raise
Segment
Solarize
Swirl
Implode
Wave
OilPaint
CharcoalDrawing
JPEG
The default preview is JPEG.
-process<command>
process a sequence of images using a process module
The command argument has the form module=arg1,arg2,arg3,...,argN
where module is the name of the module to invoke (e.g.
"analyze") and arg1,arg2,arg3,...,argN are an arbitrary number
of arguments to pass to the process module. The sequence of
images is terminated by the appearance of any option.
If the -process option appears after all of the input images,
all images are processed.
-profile<filename>
add ICM, IPTC, or generic profile to image
-profile filename adds an ICM (ICC color management), IPTC
(newswire information), or a generic profile to the image.
Use +profile icm, +profile iptc, or +profile profile_name to
remove the respective profile. Use identify -verbose to find
out what profiles are in the image file. Use +profile "*" to
remove all profiles.
To extract a profile, the -profile option is not used. Instead,
simply write the file to an image format such as APP1,8BIM,ICM, or IPTC.
For example, to extract the Exif data (which is stored in JPEG
files in the APP1 profile), use
gm convert cockatoo.jpg exifdata.app1
+progress
disable progress monitor and busy cursor
By default, when an image is displayed, a progress monitor bar
is shown in the top left corner of an existing image display
window, and the current cursor is replaced with an hourglass
cursor. Use +progress to disable the progress monitor and busy
cursor during display operations. While the progress monitor is
disabled for all operations, the busy cursor continues to be
enabled for non-display operations such as image processing.
This option is useful for non-interactive display operations, or
when a "clean" look is desired.
-quality<value>
JPEG/MIFF/PNG compression level
For the JPEG and MPEG image formats, quality is 0 (lowest image
quality and highest compression) to 100 (best quality but least
effective compression). The default quality is 75. Use the
-sampling-factor option to specify the factors for chroma
downsampling. To use the same quality value as that found by
the JPEG decoder, use the -define jpeg:preserve-settings flag.
For the MIFF image format, quality/10 is the zlib compression
level, which is 0 (worst but fastest compression) to 9 (best but
slowest). It has no effect on the image appearance, since the
compression is always lossless.
For the JPEG-2000 image format, quality is mapped using a non-
linear equation to the compression ratio required by the Jasper
library. This non-linear equation is intended to loosely
approximate the quality provided by the JPEG v1 format. The
default quality value 75 results in a request for 16:1
compression. The quality value 100 results in a request for non-
lossy compression.
For the MNG and PNG image formats, the quality value sets the
zlib compression level (quality / 10) and filter-type (quality %
10). Compression levels range from 0 (fastest compression) to
100 (best but slowest). For compression level 0, the Huffman-
only strategy is used, which is fastest but not necessarily the
worst compression.
If filter-type is 4 or less, the specified filter-type is used
for all scanlines:
0: none
1: sub
2: up
3: average
4: Paeth
If filter-type is 5, adaptive filtering is used when quality is
greater than 50 and the image does not have a color map,
otherwise no filtering is used.
If filter-type is 6, adaptive filtering with minimum-sum-of-absolute-values is used.
Only if the output is MNG, if filter-type is 7, the LOCO color
transformation and adaptive filtering with minimum-sum-of-absolute-values are used.
The default is quality is 75, which means nearly the best
compression with adaptive filtering. The quality setting has no
effect on the appearance of PNG and MNG images, since the
compression is always lossless.
For further information, see the PNG specification.
When writing a JNG image with transparency, two quality values
are required, one for the main image and one for the grayscale
image that conveys the opacity channel. These are written as a
single integer equal to the main image quality plus 1000 times
the opacity quality. For example, if you want to use quality 75
for the main image and quality 90 to compress the opacity data,
use -quality 90075.
-raise<width>x<height>
lighten or darken image edges
This will create a 3-D effect. See -geometry for details details
about the geometry specification. Offsets are not used.
Use -raise to create a raised effect, otherwise use +raise.
-random-threshold<channeltype><LOWxHIGH>
random threshold the image
The channel or channels specified in the <channeltype> argument
are reduced to binary, using an random-threshold method. The
choices for channeltype are:
all
intensity
opacity
matte
When channeltype is "all", the color samples are thresholded
into a graylevel and then that graylevel is stored in the three
color channels. Separately, the opacity channel is thresholded
into a bilevel opacity value which is stored in the opacity
channel. For each pixel, a new random number is used to
establish the threshold to be used. The threshold never exceeds
the specified maximum (HIGH) and is never less than the
specified minimum (LOW).
When channeltype is "intensity", only the color samples are
thresholded. When channeltype is "opacity" or "matte", only the
opacity channel is thresholded.
-red-primary<x>,<y>
red chromaticity primary point
-region<width>x<height>{+-}<x>{+-}<y>
apply options to a portion of the image
The x and y offsets are treated in the same manner as in -crop.
-remote
perform a X11 remote operation
The -remote command sends a command to a "gm display" or "gm
animate" which is already running. The only command recognized
at this time is the name of an image file to load. This
capability is very useful to load new images without needing to
restart GraphicsMagick (e.g. for a slide-show or to use
GraphicsMagick as the display engine for a different GUI). Also
see the +progress option for a way to disable progress
indication for a clean look while loading new images.
-render
render vector operations
Use +render to turn off rendering vector operations. This is
useful when saving the result to vector formats such as MVG or
SVG.
-resample<horizontal>x<vertical>
Resample image to specified horizontal and vertical resolution
Resize the image so that its rendered size remains the same as
the original at the specified target resolution. Either the
current image resolution units or the previously set with -units
are used to interpret the argument. For example, if a 300 DPI
image renders at 3 inches by 2 inches on a 300 DPI device, when
the image has been resampled to 72 DPI, it will render at 3
inches by 2 inches on a 72 DPI device. Note that only a small
number of image formats (e.g. JPEG, PNG, and TIFF) are capable
of storing the image resolution. For formats which do not
support an image resolution, the original resolution of the
image must be specified via -density on the command line prior
to specifying the resample resolution.
Note that Photoshop stores and obtains image resolution from a
proprietary embedded profile. If this profile exists in the
image, then Photoshop will continue to treat the image using its
former resolution, ignoring the image resolution specified in
the standard file header.
Some image formats (e.g. PNG) require use of metric or english
units so even if the original image used a particular unit
system, if it is saved to a different format prior to
resampling, then it may be necessary to specify the desired
resolution units using -units since the original units may have
been lost. In other words, do not assume that the resolution
units are restored if the image has been saved to a file.
-resize<width>x<height>{%}{@}{!}{<}{>}
resize an image
This is an alias for the -geometry option and it behaves in the
same manner. If the -filter option precedes the -resize option,
the specified filter is used.
There are some exceptions:
When used as a composite option, -resize conveys the preferred
size of the output image, while -geometry conveys the size and
placement of the compositeimage within the main image.
When used as a montage option, -resize conveys the preferred
size of the montage, while -geometry conveys information about
the tiles.
-roll{+-}<x>{+-}<y>
roll an image vertically or horizontally
See -geometry for details the geometry specification. The x and
y offsets are not affected by the -gravity option.
A negative x offset rolls the image left-to-right. A negative y
offset rolls the image top-to-bottom.
-rotate<degrees>{<}{>}
apply Paeth image rotation to the image
Use > to rotate the image only if its width exceeds the height.
< rotates the image only if its width is less than the height.
For example, if you specify -rotate "-90>" and the image size is
480x640, the image is not rotated. However, if the image is
640x480, it is rotated by -90 degrees. If you use > or <,
enclose it in quotation marks to prevent it from being
misinterpreted as a file redirection.
Empty triangles left over from rotating the image are filled
with the color defined as background (class backgroundColor).
The color is specified using the format described under the
-fill option.
-sample<geometry>
scale image using pixel sampling
See -geometry for details about the geometry specification.
-sample ignores the -filter selection if the -filter option is
present. Offsets, if present in the geometry string, are
ignored, and the -gravity option has no effect.
-sampling-factor<horizontal_factor>x<vertical_factor>
sampling factors used by JPEG or MPEG-2 encoder and YUV
decoder/encoder.
This option specifies the sampling factors to be used by the
JPEG encoder for chroma downsampling. If this option is
omitted, the JPEG library will use its own default values. When
reading or writing the YUV format and when writing the M2V
(MPEG-2) format, use -sampling-factor2x1 to specify the 4:2:2
downsampling method.
To use the same sampling factors as those found by the JPEG
decoder, use the -define jpeg:preserve-settings flag.
-scale<geometry>
scale the image.
See -geometry for details about the geometry specification.
-scale uses a simpler, faster algorithm, and it ignores the
-filter selection if the -filter option is present. Offsets, if
present in the geometry string, are ignored, and the -gravity
option has no effect.
-scene<value>
set scene number
This option sets the scene number of an image or the first image
in an image sequence.
-scenes<value-value>
range of image scene numbers to read
Each image in the range is read with the filename followed by a
period (.) and the decimal scene number. You can change this
behavior by embedding a %d,%0Nd,%o,%0No,%x,or%0Nxprintf
format specification in the file name. For example,
gm montage -scenes 5-7 image.miff
makes a montage of files image.miff.5, image.miff.6, and
image.miff.7, and
gm animate -scenes 0-12 image%02d.miff
animates files image00.miff, image01.miff, through image12.miff.
-screen
specify the screen to capture
This option indicates that the GetImage request used to obtain
the image should be done on the root window, rather than
directly on the specified window. In this way, you can obtain
pieces of other windows that overlap the specified window, and
more importantly, you can capture menus or other popups that are
independent windows but appear over the specified window.
-segment<clusterthreshold>x<smoothingthreshold>
segment an image
Segment an image by analyzing the histograms of the color
components and identifying units that are homogeneous with the
fuzzy c-means technique.
Specify clusterthreshold as the number of pixels in each
cluster must exceed the the cluster threshold to be considered
valid. Smoothingthreshold eliminates noise in the second
derivative of the histogram. As the value is increased, you can
expect a smoother second derivative. The default is 1.5. See
"Image Segmentation", below, for details.
-shade<azimuth>x<elevation>
shade the image using a distant light source
Specify azimuth and elevation as the position of the light
source. Use +shade to return the shading results as a grayscale
image.
-shadow<radius>{x<sigma>}
shadow the montage
-shared-memory
use shared memory
This option specifies whether the utility should attempt to use
shared memory for pixmaps. GraphicsMagick must be compiled with
shared memory support, and the display must support the MIT-SHM
extension. Otherwise, this option is ignored. The default is
True.
-sharpen<radius>{x<sigma>}
sharpen the image
Use a Gaussian operator of the given radius and standard
deviation (sigma).
-shave<width>x<height>{%}
shave pixels from the image edges
Specify the width of the region to be removed from both sides of
the image and the height of the regions to be removed from top
and bottom.
-shear<xdegrees>x<ydegrees>
shear the image along the X or Y axis
Use the specified positive or negative shear angle.
Shearing slides one edge of an image along the X or Y axis,
creating a parallelogram. An X direction shear slides an edge
along the X axis, while a Y direction shear slides an edge along
the Y axis. The amount of the shear is controlled by a shear
angle. For X direction shears, xdegrees is measured relative to
the Y axis, and similarly, for Y direction shears ydegrees is
measured relative to the X axis.
Empty triangles left over from shearing the image are filled
with the color defined as background (class backgroundColor).
The color is specified using the format described under the
-fill option.
-silent
operate silently
-size<width>x<height>{+offset}
width and height of the image
Use this option to specify the width and height of raw images
whose dimensions are unknown such as GRAY, RGB, or CMYK. In
addition to width and height, use -size with an offset to skip
any header information in the image or tell the number of colors
in a MAP image file, (e.g. -size 640x512+256).
For Photo CD images, choose from these sizes:
192x128
384x256
768x512
1536x1024
3072x2048
Finally, use this option to choose a particular resolution layer
of a JBIG or JPEG image (e.g. -size 1024x768).
-snaps<value>
number of screen snapshots
Use this option to grab more than one image from the X server
screen, to create an animation sequence.
-solarize<factor>
negate all pixels above the threshold level
Specify factor as the percent threshold of the intensity (0 -
99.9%).
This option produces a solarization effect seen when exposing a
photographic film to light during the development process.
-spread<amount>
displace image pixels by a random amount
Amount defines the size of the neighborhood around each pixel to
choose a candidate pixel to swap.
-stegano<offset>
hide watermark within an image
Use an offset to start the image hiding some number of pixels
from the beginning of the image. Note this offset and the image
size. You will need this information to recover the
steganographic image (e.g. display -size 320x256+35
stegano:image.png).
-stereo
composite two images to create a stereo anaglyph
The left side of the stereo pair is saved as the red channel of
the output image. The right side is saved as the green channel.
Red-green stereo glasses are required to properly view the
stereo image.
-stroke<color>
color to use when stroking a graphic primitive
The color is specified using the format described under the
-fill option.
See -draw for further details.
-strokewidth<value>
set the stroke width
See -draw for further details.
-swirl<degrees>
swirl image pixels about the center
Degrees defines the tightness of the swirl.
-text-font<name>
font for writing fixed-width text
Specifies the name of the preferred font to use in fixed
(typewriter style) formatted text. The default is 14 point
Courier.
You can tag a font to specify whether it is a PostScript,
TrueType, or OPTION1 font. For example, Courier.ttf is a
TrueType font and x:fixed is OPTION1.
-texture<filename>
name of texture to tile onto the image background
-threshold<value>{<green>,<blue>,<opacity>}{%}
threshold the image
Create an image such that any pixel sample that is equal to, or
exceeds the threshold, is reassigned the maximum intensity
otherwise the minimum intensity.
If the green or blue value is omitted, these channels use the
same value as the first one provided. If all three color values
are the same, the result is a bi-level image. If the opacity
threshold is omitted, OpaqueOpacity will be used and any
partially transparent pixel will become fully transparent. If
only a single 0 is provided, auto-thresholding will be
performed.
To generate an all-black or all-white image with the same
dimensions as the input image, you can use
gm convert -threshold 65535 in.png black.png
gm convert -threshold 0,0 in.png white.png
-tile<filename>
tile image when filling a graphic primitive
-tile<geometry>
layout of images [montage]
-title<string>
assign title to displayed image [animate,display,montage]
Use this option to assign a specific title to the image. This is
assigned to the image window and is typically displayed in the
window title bar. Optionally you can include the image
filename, type, width, height, Exif data, or other image
attribute by embedding special format characters described under
the -format option.
For example,
-title "%m:%f %wx%h"
produces an image title of MIFF:bird.miff 512x480 for an image
titled bird.miff and whose width is 512 and height is 480.
-transform
transform the image
This option applies the transformation matrix from a previous
-affine option.
gm convert -affine 2,2,-2,2,0,0 -transform bird.ppm bird.jpg
-transparent<color>
make this color transparent within the image
The color is specified using the format described under the
-fill option.
-treedepth<value>
tree depth for the color reduction algorithm
Normally, this integer value is zero or one. A value of zero or
one causes the use of an optimal tree depth for the color
reduction algorithm
An optimal depth generally allows the best representation of the
source image with the fastest computational speed and the least
amount of memory. However, the default depth is inappropriate
for some images. To assure the best representation, try values
between 2 and 8 for this parameter. Refer to quantize for more
details.
The -colors or -monochrome option, or writing to an image format
which requires color reduction, is required for this option to
take effect.
-trim trim an image
This option removes any edges that are exactly the same color as
the corner pixels. Use -fuzz to make -trim remove edges that
are nearly the same color as the corner pixels.
-type<type>
the image type
Choose from: Bilevel, Grayscale, Palette, PaletteMatte,
TrueColor, TrueColorMatte, ColorSeparation,
ColorSeparationMatte, or Optimize.
Normally, when a format supports different subformats such as
grayscale and truecolor, the encoder will try to choose an
efficient subformat. The -type option can be used to overrride
this behavior. For example, to prevent a JPEG from being
written in grayscale format even though only gray pixels are
present, use
gm convert bird.pgm -type TrueColor bird.jpg
Similarly, using -type TrueColorMatte will force the encoder to
write an alpha channel even though the image is opaque, if the
output format supports transparency.
-update<seconds>
detect when image file is modified and redisplay.
Suppose that while you are displaying an image the file that is
currently displayed is over-written. display will automatically
detect that the input file has been changed and update the
displayed image accordingly.
-units<type>
the units of image resolution
Choose from: Undefined, PixelsPerInch, or PixelsPerCentimeter.
This option is normally used in conjunction with the -density
option.
-unsharp<radius>{x<sigma>}{+<amount>}{+<threshold>}
sharpen the image with an unsharp mask operator
The -unsharp option sharpens an image. The image is convolved
with a Gaussian operator of the given radius and standard
deviation (sigma). For reasonable results, radius should be
larger than sigma. Use a radius of 0 to have the method select a
suitable radius.
The parameters are:
radius
.in 20
The radius of the Gaussian, in pixels, not counting the
center pixel (default 0).
sigma
.in 20
The standard deviation of the Gaussian, in pixels (default
1.0).
amount
.in 20
The percentage of the difference between the original and
the blur image that is added back into the original
(default 1.0).
threshold
.in 20
The threshold, as a fraction of MaxRGB, needed to apply
the difference amount (default 0.05).
-use-pixmap
use the pixmap
-verbose
print detailed information about the image
This information is printed: image scene number; image name;
image size; the image class (DirectClass or PseudoClass); the
total number of unique colors; and the number of seconds to read
and transform the image. Refer to miff for a description of the
image class.
If -colors is also specified, the total unique colors in the
image and color reduction error values are printed. Refer to
quantize for a description of these values.
-version
print GraphicsMagick version string
-view<string>
FlashPix viewing parameters
-virtual-pixel<method>
specify contents of "virtual pixels"
This option defines "virtual pixels" for use in operations that
can access pixels outside the boundaries of an image.
Choose from these methods:
Constant
.in 20
Use the image background color.
Edge
.in 20
Extend the edge pixel toward infinity (default).
Mirror
.in 20
Mirror the image.
Tile
.in 20
Tile the image.
This option affects operations that use virtual pixels such as
-blur, -sharpen, -wave, etc.
-visual<type>
animate images using this X visual type
Choose from these visual classes:
StaticGray
GrayScale
StaticColor
PseudoColor
TrueColor
DirectColor
default
visual id
The X server must support the visual you choose, otherwise an
error occurs. If a visual is not specified, the visual class
that can display the most simultaneous colors on the default
screen is chosen.
-watermark<brightness>x<saturation>
percent brightness and saturation of a watermark
-wave<amplitude>x<wavelength>
alter an image along a sine wave
Specify amplitude and wavelength of the wave.
-white-point<x>,<y>
chromaticity white point
-window<id>
make image the background of a window
id can be a window id or name. Specify root to select X’s root
window as the target window.
By default the image is tiled onto the background of the target
window. If backdrop or -geometry are specified, the image is
surrounded by the background color. Refer to XRESOURCES for
details.
The image will not display on the root window if the image has
more unique colors than the target window colormap allows. Use
-colors to reduce the number of colors.
-window-group
specify the window group
-write<filename>
write an image sequence [convert,composite]
The image sequence following the -writefilenameoption is
written out, and then processing continues with the same image
in its current state if there are additional options. To
restore the image to its original state after writing it, use
the +writefilename option.
-write<filename>
write the image to a file [display]
If filename already exists, you will be prompted as to whether
it should be overwritten.
By default, the image is written in the format that it was read
in as. To specify a particular image format, prefix filename
with the image type and a colon (e.g., ps:image) or specify the
image type as the filename suffix (e.g., image.ps). Specify file
as - for standard output. If file has the extension .Z or .gz,
the file size is compressed using compress or gzip respectively.
Precede the image file name with | to pipe to a system command.
Use -compress to specify the type of image compression.
The equivalent X resource for this option is writeFilename
(class WriteFilename). See "X Resources", below, for details.

GMANIMATE

Animate displays a sequence of images on any workstation display
running an X server. animate first determines the hardware capabilities
of the workstation. If the number of unique colors in an image is less
than or equal to the number the workstation can support, the image is
displayed in an X window. Otherwise the number of colors in the image
is first reduced to match the color resolution of the workstation
before it is displayed.
This means that a continuous-tone 24 bits-per-pixel image can display
on a 8 bit pseudo-color device or monochrome device. In most instances
the reduced color image closely resembles the original. Alternatively,
a monochrome or pseudo-color image sequence can display on a
continuous-tone 24 bits-per-pixel device.
To help prevent color flashing on X server visuals that have colormaps,
animate creates a single colormap from the image sequence. This can be
rather time consuming. You can speed this operation up by reducing the
colors in the image before you "animate" them. Use mogrify to color
reduce the images to a single colormap. See mogrify(1) for details.
Alternatively, you can use a Standard Colormap; or a static, direct, or
true color visual. You can define a Standard Colormap with xstdcmap.
See xstdcmap(1) for details. This method is recommended for colormapped
X server because it eliminates the need to compute a global colormap.

EXAMPLES

To animate a set of images of a cockatoo, use:
gm animate cockatoo.*
To animate a cockatoo image sequence while using the Standard Colormap
best, use:
xstdcmap -best
gm animate -map best cockatoo.*
To animate an image of a cockatoo without a border centered on a
backdrop, use:
gm animate +borderwidth -backdrop cockatoo.*

OPTIONS

For a more detailed description of each option, see Options, above.
-authenticate<string>
decrypt image with this password
-backdrop
display the image centered on a backdrop.
-background<color>
the background color
-bordercolor<color>
the border color
-borderwidth<geometry>
the border width
-cache<threshold>
(This option has been replaced by the -limit option)
-chop<width>x<height>{+-}<x>{+-}<y>{%}
remove pixels from the interior of an image
-colormap<type>
define the colormap type
-colors<value>
preferred number of colors in the image
-colorspace<value>
the type of colorspace
-crop<width>x<height>{+-}<x>{+-}<y>{%}
preferred size and location of the cropped image
-debug<events>
enable debug printout
-define<key>{=<value>},...
add coder/decoder specific options
-delay<1/100thsofasecond>
display the next image after pausing
-density<width>x<height>
horizontal and vertical resolution in pixels of the image
-depth<value>
depth of the image
-display<host:display[.screen]>
specifies the X server to contact
-dispose<method>
GIF disposal method
-dither
apply Floyd/Steinberg error diffusion to the image
-font<name>
use this font when annotating the image with text
-foreground<color>
define the foreground color
-gamma<value>
level of gamma correction
-geometry<width>x<height>{+-}<x>{+-}<y>{%}{@}{!}{<}{>}
preferred size and location of the Image window.
-help print usage instructions
-iconGeometry<geometry>
specify the icon geometry
-iconic
iconic animation
-interlace<type>
the type of interlacing scheme
-limit<type><value>
Disk, File, Map, or Memory resource limit
-log<string>
Specify format for debug log
-map<type>
display image using this type.
-matte store matte channel if the image has one
-mattecolor<color>
specify the color to be used with the -frame option
-monochrome
transform the image to black and white
-name name an image
-noop NOOP (no option)
-pause<seconds>
pause between animation loops [animate]
-remote
perform a X11 remote operation
-rotate<degrees>{<}{>}
apply Paeth image rotation to the image
-sampling-factor<horizontal_factor>x<vertical_factor>
sampling factors used by JPEG or MPEG-2 encoder and YUV
decoder/encoder.
-scenes<value-value>
range of image scene numbers to read
-shared-memory
use shared memory
-size<width>x<height>{+offset}
width and height of the image
-text-font<name>
font for writing fixed-width text
-title<string>
assign title to displayed image [animate,display,montage]
-treedepth<value>
tree depth for the color reduction algorithm
-trim trim an image
-verbose
print detailed information about the image
-version
print GraphicsMagick version string
-visual<type>
animate images using this X visual type
-window<id>
make image the background of a window
For a more detailed description of each option, see Options,
above.
Any option you specify on the command line remains in effect for
the group of images following it, until the group is terminated
by the appearance of any option or -noop. For example, to
animate three images, the first with 32 colors, the second with
an unlimited number of colors, and the third with only 16
colors, use:
gm animate -colors 32 cockatoo.1 -noop cockatoo.2
-colors 16 cockatoo.3
Animate options can appear on the command line or in your X
resources file. See X(1). Options on the command line supersede
values specified in your X resources file. Image filenames may
appear in any order on the command line if the image format is
MIFF (refer to miff(5) and the scene keyword is specified in the
image. Otherwise the images will display in the order they
appear on the command line.

MOUSEBUTTONS

Press any button to map or unmap the Command widget. See the next
section for more information about the Command widget.

COMMANDWIDGET

The Command widget lists a number of sub-menus and commands. They are
Animate
Open
Play
Step
Repeat
Auto Reverse
Speed
Faster
Slower
Direction
Forward
Reverse
ImageInfoHelpQuit
Menu items with a indented triangle have a sub-menu. They are
represented above as the indented items. To access a sub-menu item,
move the pointer to the appropriate menu and press a button and drag.
When you find the desired sub-menu item, release the button and the
command is executed. Move the pointer away from the sub-menu if you
decide not to execute a particular command.

KEYBOARDACCELERATORS

Ctl+O
.in 20 Press to load an image from a file.
space
.in 20 Press to display the next image in the sequence.
<
.in 20 Press to speed-up the display of the images. Refer
to -delay for more information.
>
.in 20 Press to slow the display of the images. Refer to
-delay for more information.
?
.in 20 Press to display information about the image.
Press any key or button to erase the information.
This information is printed: image name; image size; and
the total number of unique colors in the image.
F1
.in 20 Press to display helpful information about
animate(1).
Ctl-q
.in 20 Press to discard all images and exit program.

XRESOURCES

Animate options can appear on the command line or in your X resource
file. Options on the command line supersede values specified in your X
resource file. See X(1) for more information on X resources.
All animate options have a corresponding X resource. In addition, the
animate program uses the following X resources:
background(classBackground)
.in 20
Specifies the preferred color to use for the Image window
background. The default is #ccc.
borderColor(classBorderColor)
.in 20
Specifies the preferred color to use for the Image window
border. The default is #ccc.
borderWidth(classBorderWidth)
.in 20
Specifies the width in pixels of the Image window border.
The default is 2.
font(classFontorFontList)
.in 20
Specifies the name of the preferred font to use in normal
formatted text. The default is 14 point Helvetica.
foreground(classForeground)
.in 20
Specifies the preferred color to use for text within the
Image window. The default is black.
geometry(classgeometry)
.in 20
Specifies the preferred size and position of the image
window. It is not necessarily obeyed by all window
managers. Offsets, if present, are handled in X(1) style.
A negative x offset is measured from the right edge of the
screen to the right edge of the icon, and a negative y
offset is measured from the bottom edge of the screen to
the bottom edge of the icon.
iconGeometry(classIconGeometry)
.in 20
Specifies the preferred size and position of the
application when iconified. It is not necessarily obeyed
by all window managers. Offsets, if present, are handled
in the same manner as in class Geometry.
iconic(classIconic)
.in 20
This resource indicates that you would prefer that the
application’s windows initially not be visible as if the
windows had be immediately iconified by you. Window
managers may choose not to honor the application’s
request.
matteColor(classMatteColor)
.in 20
Specify the color of windows. It is used for the
backgrounds of windows, menus, and notices. A 3D effect is
achieved by using highlight and shadow colors derived from
this color. Default value: #ddd.
name(className)
.in 20
This resource specifies the name under which resources for
the application should be found. This resource is useful
in shell aliases to distinguish between invocations of an
application, without resorting to creating links to alter
the executable file name. The default is the application
name.
sharedMemory(classSharedMemory)
.in 20
This resource specifies whether animate should attempt use
shared memory for pixmaps. ImageMagick must be compiled
with shared memory support, and the display must support
the MIT-SHM extension. Otherwise, this resource is
ignored. The default is True.
text_font(classtextFont)
.in 20
Specifies the name of the preferred font to use in fixed
(typewriter style) formatted text. The default is 14 point
Courier.
title(classTitle)
.in 20
This resource specifies the title to be used for the Image
window. This information is sometimes used by a window
manager to provide some sort of header identifying the
window. The default is the image file name.

GMCOMPOSITE

composite composites (combines) images to create new images. base-image is the base image and change-image contains the changes. ouput-image is the result, and normally has the same dimensions as base-image.
The optional mask-image can be used to provide opacity information for
change-image when it has none or if you want a different mask. A mask
image is typically grayscale and the same size as base-image. If mask-image is not grayscale, it is converted to grayscale and the resulting
intensities are used as opacity information.

OPTIONS

Options are processed in command line order. Any option you specify on
the command line remains in effect only for the image that follows.
All options are reset to their default values after each image is read.
For a more detailed description of each option, see Options, above.
-authenticate<string>
decrypt image with this password
-background<color>
the background color
-blue-primary<x>,<y>
blue chromaticity primary point
-cache<threshold>
(This option has been replaced by the -limit option)
-colors<value>
preferred number of colors in the image
-colorspace<value>
the type of colorspace
-comment<string>
annotate an image with a comment
-compose<operator>
the type of image composition
-compress<type>
the type of image compression
-debug<events>
enable debug printout
-define<key>{=<value>},...
add coder/decoder specific options
-density<width>x<height>
horizontal and vertical resolution in pixels of the image
-depth<value>
depth of the image
-displace<horizontalscale>x<verticalscale>
shift image pixels as defined by a displacement map
-display<host:display[.screen]>
specifies the X server to contact
-dispose<method>
GIF disposal method
-dissolve<percent>
dissolve an image into another by the given percent
-dither
apply Floyd/Steinberg error diffusion to the image
-encoding<type>
specify the text encoding
-endian<type>
specify endianness (MSB or LSB) of output image
-filter<type>
use this type of filter when resizing an image
-font<name>
use this font when annotating the image with text
-geometry<width>x<height>{+-}<x>{+-}<y>{%}{@}{!}{<}{>}
preferred size and location of the Image window.
-gravity<type>
direction primitive gravitates to when annotating the image.
-green-primary<x>,<y>
green chromaticity primary point
-help print usage instructions
-interlace<type>
the type of interlacing scheme
-label<name>
assign a label to an image
-limit<type><value>
Disk, File, Map, or Memory resource limit
-log<string>
Specify format for debug log
-matte store matte channel if the image has one
-monochrome
transform the image to black and white
-negate
replace every pixel with its complementary color
-page<width>x<height>{+-}<x>{+-}<y>{%}{!}{<}{>}
size and location of an image canvas
-profile<filename>
add ICM, IPTC, or generic profile to image
-quality<value>
JPEG/MIFF/PNG compression level
-red-primary<x>,<y>
red chromaticity primary point
-render
render vector operations
-resize<width>x<height>{%}{@}{!}{<}{>}
resize an image
-rotate<degrees>{<}{>}
apply Paeth image rotation to the image
-sampling-factor<horizontal_factor>x<vertical_factor>
sampling factors used by JPEG or MPEG-2 encoder and YUV
decoder/encoder.
-scene<value>
set scene number
-sharpen<radius>{x<sigma>}
sharpen the image
-size<width>x<height>{+offset}
width and height of the image
-stegano<offset>
hide watermark within an image
-stereo
composite two images to create a stereo anaglyph
-treedepth<value>
tree depth for the color reduction algorithm
-trim trim an image
-type<type>
the image type
-units<type>
the units of image resolution
-unsharp<radius>{x<sigma>}{+<amount>}{+<threshold>}
sharpen the image with an unsharp mask operator
-verbose
print detailed information about the image
-version
print GraphicsMagick version string
-watermark<brightness>x<saturation>
percent brightness and saturation of a watermark
-white-point<x>,<y>
chromaticity white point
-write<filename>
write an image sequence [convert,composite]
For a more detailed description of each option, see Options,
above.

GMCONJURE

The Magick scripting language (MSL) will primarily benefit those that
want to accomplish custom image processing tasks but do not wish to
program, or those that do not have access to a Perl interpreter or a
compiler. The interpreter is called conjure and here is an example
script:
<?xml version="1.0" encoding="UTF-8"?>
<image size="400x400" >
<read filename="image.gif" />
<get width="base-width" height="base-height" />
<resize geometry="%[dimensions]" />
<get width="width" height="height" />
<print output=
"Image sized from %[base-width]x%[base-height]
to %[width]x%[height].\n" />
<write filename="image.png" />
</image>
invoked with
gm conjure -dimensions 400x400 incantation.msl
All operations will closely follow the key/value pairs defined in
PerlMagick, unless otherwise noted.
Conjure is in the early stages of development as of April 2002.
This early announcement is to allow GraphicsMagick users to contribute
ideas early in the process so when the scripting language is released
it will be useful/stable from the get-go! If you want to contribute
suggestions about the Magick scripting language (MSL), post them to the
GraphicsMagick tools list at graphicsmagick-tools @
lists.sourceforge.net.

OPTIONS

Options are processed in command line order. Any option you specify on
the command line remains in effect until it is explicitly changed by
specifying the option again with a different effect, or if it is
changed by a statement in the scripting language.
You can define your own keyword/value pairs on the command line. The
script can then use this information when setting values by including
%[keyword] in the string. For example, if you included "-dimensions
400x400" on the command line, as illustrated above, then any string
containing "%[dimensions]" would have 400x400 substituted. The
"%[string]" can be used either an entire string, such as
geometry="%[dimensions]" or as a part of a string such as
filename="%[basename].png".
The keyword can be any string except for the following reserved strings
(in any upper, lower, or mixed case variant): debug, help, and verbose,
whose usage is described below.
The value can be any string. If either the keyword or the value
contains white space or any symbols that have special meanings to your
shell such as "#", "|", or "%", enclose the string in quotation marks
or use "\" to escape the white space and special symbols.
Keywords and values are case dependent. "Key", "key", and "KEY" would
be three different keywords.
For a more detailed description of each option, see Options, above.
-debug<events>
enable debug printout
-define<key>{=<value>},...
add coder/decoder specific options
-help print usage instructions
-log<string>
Specify format for debug log
-verbose
print detailed information about the image
-version
print GraphicsMagick version string

EXAMPLES

To make a thumbnail of a JPEG image, use:
gm convert -size 120x120 cockatoo.jpg -resize 120x120
+profile "*" thumbnail.jpg
In this example, ’-size 120x120’ gives a hint to the JPEG decoder that
the image is going to be downscaled to 120x120, allowing it to run
faster by avoiding returning full-resolution images to GraphicsMagick
for the subsequent resizing operation. The ´-resize 120x120’ specifies
the desired dimensions of the output image. It will be scaled so its
largest dimension is 120 pixels. The ´+profile "*"’ removes any ICM,
EXIF, IPTC, or other profiles that might be present in the input and
aren’t needed in the thumbnail.
To convert a MIFF image of a cockatoo to a SUN raster image, use:
gm convert cockatoo.miff sun:cockatoo.ras
To convert a multi-page PostScript document to individual FAX pages,
use:
gm convert -monochrome document.ps fax:page
To convert a TIFF image to a PostScript A4 page with the image in the
lower left-hand corner, use:
gm convert -page A4+0+0 image.tiff document.ps
To convert a raw Gray image with a 128 byte header to a portable
graymap, use:
gm convert -depth 8 -size 768x512+128 gray:raw
image.pgm
In this example, "raw" is the input file. Its format is "gray" and it
has the dimensions and number of header bytes specified by the -size
option and the sample depth specified by the -depth option. The output
file is "image.pgm". The suffix ".pgm" specifies its format.
To convert a Photo CD image to a TIFF image, use:
gm convert -size 1536x1024 img0009.pcd image.tiff
gm convert img0009.pcd[4] image.tiff
To create a visual image directory of all your JPEG images, use:
gm convert ’vid:*.jpg’ directory.miff
To annotate an image with blue text using font 12x24 at position
(100,100), use:
gm convert -font helvetica -fill blue
-draw "text 100,100 Cockatoo"
bird.jpg bird.miff
To tile a 640x480 image with a JPEG texture with bumps use:
gm convert -size 640x480 tile:bumps.jpg tiled.png
To surround an icon with an ornamental border to use with Mosaic(1),
use:
gm convert -mattecolor "#697B8F" -frame 6x6 bird.jpg
icon.png
To create a MNG animation from a DNA molecule sequence, use:
gm convert -delay 20 dna.* dna.mng

OPTIONS

Options are processed in command line order. Any option you specify on
the command line remains in effect for the set of images that follows,
until the set is terminated by the appearance of any option or -noop.
Some options only affect the decoding of images and others only the
encoding. The latter can appear after the final group of input images.
For a more detailed description of each option, see Options, above.
-adjoin
join images into a single multi-image file
-affine<matrix>
drawing transform matrix
-antialias
remove pixel aliasing
-append
append a set of images
-authenticate<string>
decrypt image with this password
-average
average a set of images
-background<color>
the background color
-blue-primary<x>,<y>
blue chromaticity primary point
-blur<radius>{x<sigma>}
blur the image with a Gaussian operator
-border<width>x<height>
surround the image with a border of color
-bordercolor<color>
the border color
-box<color>
set the color of the annotation bounding box
-cache<threshold>
(This option has been replaced by the -limit option)
-channel<type>
the type of channel
-charcoal<factor>
simulate a charcoal drawing
-chop<width>x<height>{+-}<x>{+-}<y>{%}
remove pixels from the interior of an image
-clip apply the clipping path, if one is present
-coalesce
merge a sequence of images
-colorize<value>
colorize the image with the pen color
-colors<value>
preferred number of colors in the image
-colorspace<value>
the type of colorspace
-comment<string>
annotate an image with a comment
-compose<operator>
the type of image composition
-compress<type>
the type of image compression
-contrast
enhance or reduce the image contrast
-convolve<kernel>
convolve image with the specified convolution kernel
-crop<width>x<height>{+-}<x>{+-}<y>{%}
preferred size and location of the cropped image
-cycle<amount>
displace image colormap by amount
-debug<events>
enable debug printout
-deconstruct
break down an image sequence into constituent parts
-define<key>{=<value>},...
add coder/decoder specific options
-delay<1/100thsofasecond>
display the next image after pausing
-density<width>x<height>
horizontal and vertical resolution in pixels of the image
-depth<value>
depth of the image
-despeckle
reduce the speckles within an image
-display<host:display[.screen]>
specifies the X server to contact
-dispose<method>
GIF disposal method
-dither
apply Floyd/Steinberg error diffusion to the image
-draw<string>
annotate an image with one or more graphic primitives
-edge<radius>
detect edges within an image
-emboss<radius>
emboss an image
-encoding<type>
specify the text encoding
-endian<type>
specify endianness (MSB or LSB) of output image
-enhance
apply a digital filter to enhance a noisy image
-equalize
perform histogram equalization to the image
-fill<color>
color to use when filling a graphic primitive
-filter<type>
use this type of filter when resizing an image
-flatten
flatten a sequence of images
-flip create a "mirror image"
-flop create a "mirror image"
-font<name>
use this font when annotating the image with text
-frame<width>x<height>+<outerbevelwidth>+<innerbevelwidth>
surround the image with an ornamental border
-fuzz<distance>{%}
colors within this distance are considered equal
-gamma<value>
level of gamma correction
-Gaussian<radius>{x<sigma>}
blur the image with a Gaussian operator
-geometry<width>x<height>{+-}<x>{+-}<y>{%}{@}{!}{<}{>}
preferred size and location of the Image window.
-gravity<type>
direction primitive gravitates to when annotating the image.
-green-primary<x>,<y>
green chromaticity primary point
-help print usage instructions
-implode<factor>
implode image pixels about the center
-intent<type>
use this type of rendering intent when managing the image color
-interlace<type>
the type of interlacing scheme
-label<name>
assign a label to an image
-lat<width>x<height>{+-}<offset>{%}
perform local adaptive thresholding
-level<black_point>{,<gamma>}{,<white_point>}{%}
adjust the level of image contrast
-limit<type><value>
Disk, File, Map, or Memory resource limit
-list<type>
the type of list
-log<string>
Specify format for debug log
-loop<iterations>
add Netscape loop extension to your GIF animation
-map<filename>
choose a particular set of colors from this image
-mask<filename>
Specify a clipping mask
-matte store matte channel if the image has one
-mattecolor<color>
specify the color to be used with the -frame option
-median<radius>
apply a median filter to the image
-modulatebrightness[,saturation[,hue]]
vary the brightness, saturation, and hue of an image
-monochrome
transform the image to black and white
-morph<frames>
morphs an image sequence
-mosaic
create a mosaic from an image or an image sequence
-negate
replace every pixel with its complementary color
-noise<radius|type>
add or reduce noise in an image
-noop NOOP (no option)
-normalize
transform image to span the full range of color values
-opaque<color>
change this color to the pen color within the image
-operatorchanneloperatorrvalue[%]
apply a mathematical or bitwise operator to an image channel
-ordered-dither<channeltype><NxN>
ordered dither the image
-page<width>x<height>{+-}<x>{+-}<y>{%}{!}{<}{>}
size and location of an image canvas
-paint<radius>
simulate an oil painting
-pen<color>
(This option has been replaced by the -fill option)
-ping efficiently determine image characteristics
-pointsize<value>
pointsize of the PostScript, OPTION1, or TrueType font
-preview<type>
image preview type
-process<command>
process a sequence of images using a process module
-profile<filename>
add ICM, IPTC, or generic profile to image
-quality<value>
JPEG/MIFF/PNG compression level
-raise<width>x<height>
lighten or darken image edges
-random-threshold<channeltype><LOWxHIGH>
random threshold the image
-red-primary<x>,<y>
red chromaticity primary point
-region<width>x<height>{+-}<x>{+-}<y>
apply options to a portion of the image
-render
render vector operations
-resample<horizontal>x<vertical>
Resample image to specified horizontal and vertical resolution
-resize<width>x<height>{%}{@}{!}{<}{>}
resize an image
-roll{+-}<x>{+-}<y>
roll an image vertically or horizontally
-rotate<degrees>{<}{>}
apply Paeth image rotation to the image
-sample<geometry>
scale image using pixel sampling
-sampling-factor<horizontal_factor>x<vertical_factor>
sampling factors used by JPEG or MPEG-2 encoder and YUV
decoder/encoder.
-scale<geometry>
scale the image.
-scene<value>
set scene number
-segment<clusterthreshold>x<smoothingthreshold>
segment an image
-shade<azimuth>x<elevation>
shade the image using a distant light source
-sharpen<radius>{x<sigma>}
sharpen the image
-shave<width>x<height>{%}
shave pixels from the image edges
-shear<xdegrees>x<ydegrees>
shear the image along the X or Y axis
-size<width>x<height>{+offset}
width and height of the image
-solarize<factor>
negate all pixels above the threshold level
-spread<amount>
displace image pixels by a random amount
-stroke<color>
color to use when stroking a graphic primitive
-strokewidth<value>
set the stroke width
-swirl<degrees>
swirl image pixels about the center
-texture<filename>
name of texture to tile onto the image background
-threshold<value>{<green>,<blue>,<opacity>}{%}
threshold the image
-tile<filename>
tile image when filling a graphic primitive
-transform
transform the image
-transparent<color>
make this color transparent within the image
-treedepth<value>
tree depth for the color reduction algorithm
-trim trim an image
-type<type>
the image type
-units<type>
the units of image resolution
-unsharp<radius>{x<sigma>}{+<amount>}{+<threshold>}
sharpen the image with an unsharp mask operator
-use-pixmap
use the pixmap
-verbose
print detailed information about the image
-version
print GraphicsMagick version string
-view<string>
FlashPix viewing parameters
-virtual-pixel<method>
specify contents of "virtual pixels"
-wave<amplitude>x<wavelength>
alter an image along a sine wave
-white-point<x>,<y>
chromaticity white point
-write<filename>
write an image sequence [convert,composite]
For a more detailed description of each option, see Options,
above.

GMDISPLAY

Display is a machine architecture independent image processing and
display program. It can display an image on any workstation screen
running an X server. Display can read and write many of the more
popular image formats (e.g. JPEG, TIFF, PNM, PhotoCD, etc.).
With display, you can perform these functions on an image:
o load an image from a file
o display the next image
o display the former image
o display a sequence of images as a slide show
o write the image to a file
o print the image to a PostScript printer
o delete the image file
o create a Visual Image Directory
o select the image to display by its thumbnail rather than
name
o undo last image transformation
o copy a region of the image
o paste a region to the image
o restore the image to its original size
o refresh the image
o half the image size
o double the image size
o resize the image
o crop the image
o cut the image
o flop image in the horizontal direction
o flip image in the vertical direction
o rotate the image 90 degrees clockwise
o rotate the image 90 degrees counter-clockwise
o rotate the image
o shear the image
o roll the image
o trim the image edges
o invert the colors of the image
o vary the color brightness
o vary the color saturation
o vary the image hue
o gamma correct the image
o sharpen the image contrast
o dull the image contrast
o perform histogram equalization on the image
o perform histogram normalization on the image
o negate the image colors
o convert the image to grayscale
o set the maximum number of unique colors in the image
o reduce the speckles within an image
o eliminate peak noise from an image
o detect edges within the image
o emboss an image
o segment the image by color
o simulate an oil painting
o simulate a charcoal drawing
o annotate the image with text
o draw on the image
o edit an image pixel color
o edit the image matte information
o composite an image with another
o add a border to the image
o surround image with an ornamental border
o apply image processing techniques to a region of interest
o display information about the image
o zoom a portion of the image
o show a histogram of the image
o display image to background of a window
o set user preferences
o display information about this program
o discard all images and exit program
o change the level of magnification
o display images specified by a World Wide Web (WWW) uniform
resource locator (URL)

EXAMPLES

To scale an image of a cockatoo to exactly 640 pixels in width and 480
pixels in height and position the window at location (200,200), use:
gm display -geometry 640x480+200+200! cockatoo.miff
To display an image of a cockatoo without a border centered on a
backdrop, use:
gm display +borderwidth -backdrop cockatoo.miff
To tile a slate texture onto the root window, use:
gm display -size 1280x1024 -window root slate.png
To display a visual image directory of all your JPEG images, use:
gm display ’vid:*.jpg’
To display a MAP image that is 640 pixels in width and 480 pixels in
height with 256 colors, use:
gm display -size 640x480+256 cockatoo.map
To display an image of a cockatoo specified with a WorldWideWeb(WWW)
uniform resource locator (URL), use:
gm display ftp://wizards.dupont.com/images/cockatoo.jpg
To display histogram of an image, use:
gm convert file.jpg HISTOGRAM:- | display -

OPTIONS

Options are processed in command line order. Any option you specify on
the command line remains in effect until it is explicitly changed by
specifying the option again with a different effect. For example to
display three images, the first with 32 colors, the second with an
unlimited number of colors, and the third with only 16 colors, use:
gm display -colors 32 cockatoo.miff -noop duck.miff
-colors 16 macaw.miff
Display options can appear on the command line or in your X resources
file. See X(1). Options on the command line supersede values specified
in your X resources file.
For a more detailed description of each option, see Options, above.
-authenticate<string>
decrypt image with this password
-backdrop
display the image centered on a backdrop.
-background<color>
the background color
-border<width>x<height>
surround the image with a border of color
-bordercolor<color>
the border color
-borderwidth<geometry>
the border width
-cache<threshold>
(This option has been replaced by the -limit option)
-colormap<type>
define the colormap type
-colors<value>
preferred number of colors in the image
-colorspace<value>
the type of colorspace
-comment<string>
annotate an image with a comment
-compress<type>
the type of image compression
-contrast
enhance or reduce the image contrast
-crop<width>x<height>{+-}<x>{+-}<y>{%}
preferred size and location of the cropped image
-debug<events>
enable debug printout
-define<key>{=<value>},...
add coder/decoder specific options
-delay<1/100thsofasecond>
display the next image after pausing
-density<width>x<height>
horizontal and vertical resolution in pixels of the image
-depth<value>
depth of the image
-despeckle
reduce the speckles within an image
-display<host:display[.screen]>
specifies the X server to contact
-dispose<method>
GIF disposal method
-dither
apply Floyd/Steinberg error diffusion to the image
-edge<radius>
detect edges within an image
-endian<type>
specify endianness (MSB or LSB) of output image
-enhance
apply a digital filter to enhance a noisy image
-filter<type>
use this type of filter when resizing an image
-flip create a "mirror image"
-flop create a "mirror image"
-font<name>
use this font when annotating the image with text
-foreground<color>
define the foreground color
-frame<width>x<height>+<outerbevelwidth>+<innerbevelwidth>
surround the image with an ornamental border
-gamma<value>
level of gamma correction
-geometry<width>x<height>{+-}<x>{+-}<y>{%}{@}{!}{<}{>}
preferred size and location of the Image window.
-help print usage instructions
-iconGeometry<geometry>
specify the icon geometry
-iconic
iconic animation
-immutable
make image immutable
-interlace<type>
the type of interlacing scheme
-label<name>
assign a label to an image
-limit<type><value>
Disk, File, Map, or Memory resource limit
-log<string>
Specify format for debug log
-magnify<factor>
magnify the image
-map<type>
display image using this type.
-matte store matte channel if the image has one
-mattecolor<color>
specify the color to be used with the -frame option
-monochrome
transform the image to black and white
-name name an image
-negate
replace every pixel with its complementary color
-noop NOOP (no option)
-page<width>x<height>{+-}<x>{+-}<y>{%}{!}{<}{>}
size and location of an image canvas
+progress
disable progress monitor and busy cursor
-quality<value>
JPEG/MIFF/PNG compression level
-raise<width>x<height>
lighten or darken image edges
-remote
perform a X11 remote operation
-roll{+-}<x>{+-}<y>
roll an image vertically or horizontally
-rotate<degrees>{<}{>}
apply Paeth image rotation to the image
-sample<geometry>
scale image using pixel sampling
-sampling-factor<horizontal_factor>x<vertical_factor>
sampling factors used by JPEG or MPEG-2 encoder and YUV
decoder/encoder.
-scenes<value-value>
range of image scene numbers to read
-segment<clusterthreshold>x<smoothingthreshold>
segment an image
-shared-memory
use shared memory
-sharpen<radius>{x<sigma>}
sharpen the image
-size<width>x<height>{+offset}
width and height of the image
-text-font<name>
font for writing fixed-width text
-texture<filename>
name of texture to tile onto the image background
-title<string>
assign title to displayed image [animate,display,montage]
-treedepth<value>
tree depth for the color reduction algorithm
-trim trim an image
-update<seconds>
detect when image file is modified and redisplay.
-use-pixmap
use the pixmap
-verbose
print detailed information about the image
-version
print GraphicsMagick version string
-visual<type>
animate images using this X visual type
-window<id>
make image the background of a window
-window-group
specify the window group
-write<filename>
write the image to a file [display]
For a more detailed description of each option, see Options,
above.

MOUSEBUTTONS

The effects of each button press is described below. Three buttons are
required. If you have a two button mouse, button 1 and 3 are returned.
Press ALT and button 3 to simulate button 2.
1 Press this button to map or unmap the Command widget . See the
next section for more information about the Command widget.
2 Press and drag to define a region of the image to magnify.
3 Press and drag to choose from a select set of display(1)
commands. This button behaves differently if the image being
displayed is a visual image directory. Choose a particular tile
of the directory and press this button and drag to select a
command from a pop-up menu. Choose from these menu items:
Open
Next
Former
Delete
Update
If you choose Open, the image represented by the tile is
displayed. To return to the visual image directory, choose Next
from the Command widget (refer to Command Widget). Next and
Former moves to the next or former image respectively. Choose
Delete to delete a particular image tile. Finally, choose Update
to synchronize all the image tiles with their respective images.
See montage and miff for more details.

KEYBOARDACCELERATORS

Accelerators are one or two key presses that effect a particular
command. The keyboard accelerators that display understands is:
Ctl+O Press to load an image from a file.
space Press to display the next image.
If the image is a multi-paged document such as a PostScript document,
you can skip ahead several pages by preceding this command with a
number. For example to display the fourth page beyond the current
page, press 4space.
backspace Press to display the former image.
If the image is a multi-paged document such as a PostScript document,
you can skip behind several pages by preceding this command with a
number. For example to display the fourth page preceding the current
page, press 4n.
Ctl-S Press to save the image to a file.
Ctl-P Press to print the image to a
PostScript printer.
Ctl-D Press to delete an image file.
Ctl-N Press to create a blank canvas.
Ctl-Q Press to discard all images and exit program.
Ctl+Z Press to undo last image transformation.
Ctl+R Press to redo last image transformation.
Ctl-X Press to cut a region of
the image.
Ctl-C Press to copy a region of
the image.
Ctl-V Press to paste a region to
the image.
< Press to halve the image size.
. Press to return to the original image size.
> Press to double the image size.
% Press to resize the image to a width and height
you specify.
Cmd-A Press to make any image transformations
permanent.
By default, any image size transformations are
applied to the original image to create the
image displayed on the X server. However, the
transformations are not permanent (i.e. the
original image does not change size only the
X image does). For example, if you press ">"
the X image will appear to double in size, but
the original image will in fact remain the same
size. To force the original image to double in
size, press ">" followed by "Cmd-A".
@ Press to refresh the image window.
C Press to crop the image.
[ Press to chop the image.
H Press to flop image in the horizontal direction.
V Press to flip image in the vertical direction.
/ Press to rotate the image 90 degrees clockwise.
\ Press to rotate the image 90 degrees
counter-clockwise.
* Press to rotate the image
the number of degrees you specify.
S Press to shear the image the number of degrees
you specify.
R Press to roll the image.
T Press to trim the image edges.
Shft-H Press to vary the color hue.
Shft-S Press to vary the color saturation.
Shft-L Press to vary the image brightness.
Shft-G Press to gamma correct the image.
Shft-C Press to spiff up the image contrast.
Shft-Z Press to dull the image contrast.
= Press to perform histogram equalization on
the image.
Shft-N Press to perform histogram normalization on
the image.
Shft-~ Press to negate the colors of the image.
. Press to convert the image colors to gray.
Shft-# Press to set the maximum number of unique
colors in the image.
F2 Press to reduce the speckles in an image.
F2 Press to emboss an image.
F4 Press to eliminate peak noise from an image.
F5 Press to add noise to an image.
F6 Press to sharpen an image.
F7 Press to blur image an image.
F8 Press to threshold the image.
F9 Press to detect edges within an image.
F10 Press to displace pixels by a random amount.
F11 Press to shade the image using a distant light
source.
F12 Press to lighten or darken image edges to
create a 3-D effect.
F13 Press to segment the image by color.
Meta-S Press to swirl image pixels about the center.
Meta-I Press to implode image pixels about the center.
Meta-W Press to alter an image along a sine wave.
Meta-P Press to simulate an oil painting.
Meta-C Press to simulate a charcoal drawing.
Alt-X Press to composite the image
with another.
Alt-A Press to annotate the image with text.
Alt-D Press to draw a line on the image.
Alt-P Press to edit an image pixel color.
Alt-M Press to edit the image matte information.
Alt-X Press to composite the image with another.
Alt-A Press to add a border to the image.
Alt-F Press to add a ornamental frame to the image.
Alt-Shft-! Press to add an image comment.
Ctl-A Press to apply image processing techniques to a
region of interest.
Shft-? Press to display information about the image.
Shft-+ Press to map the zoom image window.
Shft-P Press to preview an image enhancement, effect,
or f/x.
F1 Press to display helpful information about
the "display" utility.
Find Press to browse documentation about
GraphicsMagick.
1-9 Press to change the level of magnification.
Use the arrow keys to move the image one pixel up, down, left, or right
within the magnify window. Be sure to first map the magnify window by
pressing button 2.
Press ALT and one of the arrow keys to trim off one pixel from any side
of the image.

XRESOURCES

Display options can appear on the command line or in your X resource
file. Options on the command line supersede values specified in your X
resource file. See X(1) for more information on X resources.
Most display options have a corresponding X resource. In addition,
display uses the following X resources:
background(classBackground)
Specifies the preferred color to use for the Image window
background. The default is #ccc.
borderColor(classBorderColor)
Specifies the preferred color to use for the Image window
border. The default is #ccc.
borderWidth(classBorderWidth)
Specifies the width in pixels of the image window border. The
default is 2.
browseCommand(classbrowseCommand)
Specifies the name of the preferred browser when displaying
GraphicsMagick documentation. The default is netscape %s.
confirmExit(classConfirmExit)Display pops up a dialog box to confirm exiting the program
when exiting the program. Set this resource to False to exit
without a confirmation.
displayGamma(classDisplayGamma)
Specifies the gamma of the X server. You can apply separate
gamma values to the red, green, and blue channels of the image
with a gamma value list delineated with slashes (i.e.
1.7/2.3/1.2). The default is 2.2.
displayWarnings(classDisplayWarnings)Display pops up a dialog box whenever a warning message occurs.
Set this resource to False to ignore warning messages.
font(classFontList)
Specifies the name of the preferred font to use in normal
formatted text. The default is 14 point Helvetica.
font[1-9](classFont[1-9])
Specifies the name of the preferred font to use when annotating
the image window with text. The default fonts are fixed,
variable, 5x8, 6x10, 7x13bold, 8x13bold, 9x15bold, 10x20, and
12x24.
foreground(classForeground)
Specifies the preferred color to use for text within the image
window. The default is black.
gammaCorrect(classgammaCorrect)
This resource, if true, will lighten or darken an image of
known gamma to match the gamma of the display (see resource
displayGamma). The default is True.
geometry(classGeometry)
Specifies the preferred size and position of the image window.
It is not necessarily obeyed by all window managers.
Offsets, if present, are handled in X(1) style. A negative x
offset is measured from the right edge of the screen to the
right edge of the icon, and a negative y offset is measured from
the bottom edge of the screen to the bottom edge of the icon.
iconGeometry(classIconGeometry)
Specifies the preferred size and position of the application
when iconified. It is not necessarily obeyed by all window
managers.
Offsets, if present, are handled in the same manner as in class
Geometry.
iconic(classIconic)
This resource indicates that you would prefer that the
application’s windows initially not be visible as if the windows
had be immediately iconified by you. Window managers may choose
not to honor the application’s request.
magnify(classMagnify)
specifies an integral factor by which the image should be
enlarged. The default is 3. This value only affects the
magnification window which is invoked with button number 3 after
the image is displayed.
matteColor(classMatteColor)
Specify the color of windows. It is used for the backgrounds of
windows, menus, and notices. A 3D effect is achieved by using
highlight and shadow colors derived from this color. Default
value: #697B8F.
name(className)
This resource specifies the name under which resources for the
application should be found. This resource is useful in shell
aliases to distinguish between invocations of an application,
without resorting to creating links to alter the executable file
name. The default is the application name.
pen[1-9](classPen[1-9])
Specifies the color of the preferred font to use when
annotating the image window with text. The default colors are
black, blue, green, cyan, gray, red, magenta, yellow, and white.
printCommand(classPrintCommand)
This command is executed whenever Print is issued. In general,
it is the command to print PostScript to your printer. Default
value: lp -c -s %i.
sharedMemory(classSharedMemory)
This resource specifies whether display should attempt use
shared memory for pixmaps. GraphicsMagick must be compiled with
shared memory support, and the display must support the MIT-SHM
extension. Otherwise, this resource is ignored. The default is
True.
textFont(classtextFont)
Specifies the name of the preferred font to use in fixed
(typewriter style) formatted text. The default is 14 point
Courier.
title(classTitle)
This resource specifies the title to be used for the image
window. This information is sometimes used by a window manager
to provide a header identifying the window. The default is the
image file name.
undoCache(classUndoCache)
Specifies, in mega-bytes, the amount of memory in the undo edit
cache. Each time you modify the image it is saved in the undo
edit cache as long as memory is available. You can subsequently
undo one or more of these transformations. The default is 16
Megabytes.
usePixmap(classUsePixmap)
Images are maintained as a XImage by default. Set this resource
to True to utilize a server Pixmap instead. This option is
useful if your image exceeds the dimensions of your server
screen and you intend to pan the image. Panning is much faster
with Pixmaps than with a XImage. Pixmaps are considered a
precious resource, use them with discretion.
To set the geometry of the Magnify or Pan or window, use the
geometry resource. For example, to set the Pan window geometry
to 256x256, use:
gm display.pan.geometry: 256x256

IMAGELOADING

To select an image to display, choose Open of the File sub-menu from
the Command widget. A file browser is displayed. To choose a
particular image file, move the pointer to the filename and press any
button. The filename is copied to the text window. Next, press Open or
press the RETURN key. Alternatively, you can type the image file name
directly into the text window. To descend directories, choose a
directory name and press the button twice quickly. A scrollbar allows a
large list of filenames to be moved through the viewing area if it
exceeds the size of the list area.
You can trim the list of file names by using shell globbing characters.
For example, type *.jpg to list only files that end with .jpg.
To select your image from the X server screen instead of from a file,
Choose Grab of the Open widget.

VISUALIMAGEDIRECTORY

To create a Visual Image Directory, choose Visual Directory of the File
sub-menu from the Command widget . A file browser is displayed. To
create a Visual Image Directory from all the images in the current
directory, press Directory or press the RETURNkey. Alternatively, you
can select a set of image names by using shell globbing characters. For
example, type *.jpg to include only files that end with .jpg. To
descend directories, choose a directory name and press the button twice
quickly. A scrollbar allows a large list of filenames to be moved
through the viewing area if it exceeds the size of the list area.
After you select a set of files, they are turned into thumbnails and
tiled onto a single image. Now move the pointer to a particular
thumbnail and press button3 and drag. Finally, select Open. The image
represented by the thumbnail is displayed at its full size. Choose Next
from the File sub-menu of the Command widget to return to the Visual
Image Directory.

IMAGECUTTING

Note that cut information for image window is not retained for
colormapped X server visuals (e.g. StaticColor, StaticColor, GRAYScale,
PseudoColor). Correct cutting behavior may require a TrueColor or
DirectColor visual or a StandardColormap.
To begin, press choose Cut of the Edit sub-menu from the Command
widget. Alternatively, press F3 in the image window.
A small window appears showing the location of the cursor in the image
window. You are now in cut mode. In cut mode, the Command widget has
these options:
HelpDismiss
To define a cut region, press button 1 and drag. The cut region is
defined by a highlighted rectangle that expands or contracts as it
follows the pointer. Once you are satisfied with the cut region,
release the button. You are now in rectify mode. In rectify mode, the
Command widget has these options:
CutHelpDismiss
You can make adjustments by moving the pointer to one of the cut
rectangle corners, pressing a button, and dragging. Finally, press Cut
to commit your copy region. To exit without cutting the image, press
Dismiss.

IMAGECOPYING

To begin, press choose Copy of the Edit sub-menu from the Command
widget. Alternatively, press F4 in the image window.
A small window appears showing the location of the cursor in the image
window. You are now in copy mode. In copy mode, the Command widget has
these options:
Help
Dismiss
To define a copy region, press button 1 and drag. The copy region is
defined by a highlighted rectangle that expands or contracts as it
follows the pointer. Once you are satisfied with the copy region,
release the button. You are now in rectify mode. In rectify mode, the
Command widget has these options:
Copy
Help
Dismiss
You can make adjustments by moving the pointer to one of the copy
rectangle corners, pressing a button, and dragging. Finally, press Copy
to commit your copy region. To exit without copying the image, press
Dismiss.

IMAGEPASTING

To begin, press choose Paste of the Edit sub-menu from the Command
widget. Alternatively, press F5 in the image window.
A small window appears showing the location of the cursor in the image
window. You are now in Paste mode. To exit immediately, press Dismiss.
In Paste mode, the Command widget has these options:
Operators
over
in
out
atop
xor
plus
minus
add
subtract
difference
multiply
bumpmap
replace
HelpDismiss
Choose a composite operation from the Operators sub-menu of the Command
widget. How each operator behaves is described below. imagewindow is
the image currently displayed on your X server and image is the image
obtained with the File Browser widget.
over The result is the union of the two image shapes, with image
obscuring imagewindow in the region of overlap.
in The result is simply image cut by the shape of imagewindow.
None of the image data of image window is in the result.
out The resulting image is image with the shape of imagewindow cut
out.
atop The result is the same shape as imagewindow, with image
obscuring imagewindow where the image shapes overlap. Note this
differs from over because the portion of image outside imagewindow’s shape does not appear in the result.
xor The result is the image data from both image and imagewindow
that is outside the overlap region. The overlap region is blank.
plus The result is just the sum of the image data. Output values are
cropped to the maximum value (no overflow). This operation is
independent of the matte channels.
minus The result of image - imagewindow, with underflow cropped to
zero. The matte channel is ignored (set to opaque, full
coverage).
add The result of image + imagewindow, with overflow wrapping
around (mod MaxRGB+1).
subtract
The result of image - imagewindow, with underflow wrapping
around (mod MaxRGB+1). The add and subtract operators can be
used to perform reversible transformations.
difference
The result of abs(image - imagewindow). This is useful for
comparing two very similar images.
multiply
The result of image * imagewindow. This is useful for the
creation of drop-shadows.
bumpmap
The result of imagewindow shaded by window.
replace
The resulting image is imagewindow replaced with image. Here
the matte information is ignored.
The image compositor requires a matte, or alpha channel in the
image for some operations. This extra channel usually defines a
mask which represents a sort of a cookie-cutter for the image.
This is the case when matte is 255 (full coverage) for pixels
inside the shape, zero outside, and between zero and 255 on the
boundary. If image does not have a matte channel, it is
initialized with 0 for any pixel matching in color to pixel
location (0,0), otherwise 255. See Matte Editing for a method of
defining a matte channel.
Note that matte information for image window is not retained for
colormapped X server visuals (e.g. StaticColor,StaticColor,GrayScale,PseudoColor). Correct compositing behavior may
require a TrueColor or DirectColor visual or a StandardColormap.
Choosing a composite operator is optional. The default operator
is replace. However, you must choose a location to composite
your image and press button 1. Press and hold the button before
releasing and an outline of the image will appear to help you
identify your location.
The actual colors of the pasted image is saved. However, the
color that appears in image window may be different. For
example, on a monochrome screen image window will appear black
or white even though your pasted image may have many colors. If
the image is saved to a file it is written with the correct
colors. To assure the correct colors are saved in the final
image, any PseudoClass image is promoted to DirectClass. To
force a PseudoClass image to remain PseudoClass, use -colors.

IMAGECROPPING

To begin, press choose Crop of the Transform submenu from the Command
widget. Alternatively, press [ in the image window.
A small window appears showing the location of the cursor in the image
window. You are now in crop mode. In crop mode, the Command widget has
these options:
HelpDismiss
To define a cropping region, press button 1 and drag. The cropping
region is defined by a highlighted rectangle that expands or contracts
as it follows the pointer. Once you are satisfied with the cropping
region, release the button. You are now in rectify mode. In rectify
mode, the Command widget has these options:
CropHelpDismiss
You can make adjustments by moving the pointer to one of the cropping
rectangle corners, pressing a button, and dragging. Finally, press Crop
to commit your cropping region. To exit without cropping the image,
press Dismiss.

IMAGECHOPPING

An image is chopped interactively. There is no command line argument to
chop an image. To begin, choose Chop of the Transform sub-menu from the
Command widget. Alternatively, press ] in the Image window.
You are now in Chop mode. To exit immediately, press Dismiss. In Chop
mode, the Command widget has these options:
Direction
horizontal
vertical
HelpDismiss
If the you choose the horizontal direction (this is the default), the
area of the image between the two horizontal endpoints of the chop line
is removed. Otherwise, the area of the image between the two vertical
endpoints of the chop line is removed.
Select a location within the image window to begin your chop, press and
hold any button. Next, move the pointer to another location in the
image. As you move a line will connect the initial location and the
pointer. When you release the button, the area within the image to chop
is determined by which direction you choose from the Command widget.
To cancel the image chopping, move the pointer back to the starting
point of the line and release the button.

IMAGEROTATION

Press the / key to rotate the image 90 degrees or \ to rotate -90
degrees. To interactively choose the degree of rotation, choose
Rotate... of the Transform submenu from the Command Widget.
Alternatively, press * in the image window.
A small horizontal line is drawn next to the pointer. You are now in
rotate mode. To exit immediately, press Dismiss. In rotate mode, the
Command widget has these options:
PixelColor
black
blue
cyan
green
gray
red
magenta
yellow
white
Browser...
Direction
horizontal
vertical
HelpDismiss
Choose a background color from the Pixel Color sub-menu. Additional
background colors can be specified with the color browser. You can
change the menu colors by setting the X resources pen1 through pen9.
If you choose the color browser and press Grab, you can select the
background color by moving the pointer to the desired color on the
screen and press any button.
Choose a point in the image window and press this button and hold.
Next, move the pointer to another location in the image. As you move a
line connects the initial location and the pointer. When you release
the button, the degree of image rotation is determined by the slope of
the line you just drew. The slope is relative to the direction you
choose from the Direction sub-menu of the Command widget.
To cancel the image rotation, move the pointer back to the starting
point of the line and release the button.

IMAGEANNOTATION

An image is annotated interactively. There is no command line argument
to annotate an image. To begin, choose Annotate of the ImageEdit sub-
menu from the Command widget. Alternatively, press a in the image
window.
A small window appears showing the location of the cursor in the image
window. You are now in annotate mode. To exit immediately, press
Dismiss. In annotate mode, the Command widget has these options:
FontName
fixed
variable
5x8
6x10
7x13bold
8x13bold
9x15bold
10x20
12x24
Browser...
FontColor
black
blue
cyan
green
gray
red
magenta
yellow
white
transparent
Browser...
BoxColor
black
blue
cyan
green
gray
red
magenta
yellow
white
transparent
Browser...
RotateText
-90
-45
-30
0
30
45
90
180
Dialog...
HelpDismiss
Choose a font name from the FontName sub-menu. Additional font names
can be specified with the font browser. You can change the menu names
by setting the X resources font1 through font9.
Choose a font color from the FontColor sub-menu. Additional font
colors can be specified with the color browser. You can change the menu
colors by setting the X resources pen1 through pen9.
If you select the color browser and press Grab, you can choose the font
color by moving the pointer to the desired color on the screen and
press any button.
If you choose to rotate the text, choose RotateText from the menu and
select an angle. Typically you will only want to rotate one line of
text at a time. Depending on the angle you choose, subsequent lines may
end up overwriting each other.
Choosing a font and its color is optional. The default font is fixed
and the default color is black. However, you must choose a location to
begin entering text and press a button. An underscore character will
appear at the location of the pointer. The cursor changes to a pencil
to indicate you are in text mode. To exit immediately, press Dismiss.
In text mode, any key presses will display the character at the
location of the underscore and advance the underscore cursor. Enter
your text and once completed press Apply to finish your image
annotation. To correct errors press BACKSPACE. To delete an entire
line of text, press DELETE. Any text that exceeds the boundaries of
the image window is automatically continued onto the next line.
The actual color you request for the font is saved in the image.
However, the color that appears in your Image window may be different.
For example, on a monochrome screen the text will appear black or white
even if you choose the color red as the font color. However, the image
saved to a file with -write is written with red lettering. To assure
the correct color text in the final image, any PseudoClass image is
promoted to DirectClass (see miff(5)). To force a PseudoClass image to
remain PseudoClass, use -colors.

IMAGECOMPOSITING

An image composite is created interactively. Thereisnocommandlineargumenttocompositeanimage. To begin, choose Composite of the ImageEdit from the Command widget. Alternatively, press x in the Image
window.
First a popup window is displayed requesting you to enter an image
name. Press Composite, Grab or type a file name. Press Cancel if you
choose not to create a composite image. When you choose Grab, move the
pointer to the desired window and press any button.
If the Composite image does not have any matte information, you are
informed and the file browser is displayed again. Enter the name of a
mask image. The image is typically grayscale and the same size as the
composite image. If the image is not grayscale, it is converted to
grayscale and the resulting intensities are used as matte information.
A small window appears showing the location of the cursor in the image
window. You are now in composite mode. To exit immediately, press
Dismiss. In composite mode, the Command widget has these options:
Operators
over
in
out
atop
xor
plus
minus
add
subtract
difference
bumpmap
replace
BlendDisplaceHelpDismiss
Choose a composite operation from the Operators sub-menu of the Command
widget. How each operator behaves is described below. image window is
the image currently displayed on your X server and image is the image
obtained
over The result is the union of the two image shapes, with image
obscuring imagewindow in the region of overlap.
in The result is simply image cut by the shape of imagewindow.
None of the image data of image window is in the result.
out The resulting image is image with the shape of imagewindow cut
out.
atop The result is the same shape as imagewindow, with image
obscuring imagewindow where the image shapes overlap. Note this
differs from over because the portion of image outside imagewindow’s shape does not appear in the result.
xor The result is the image data from both image and imagewindow
that is outside the overlap region. The overlap region is blank.
plus The result is just the sum of the image data. Output values are
cropped to 255 (no overflow). This operation is independent of
the matte channels.
minus The result of image - imagewindow, with underflow cropped to
zero. The matte channel is ignored (set to 255, full coverage).
add The result of image + imagewindow, with overflow wrapping
around (mod 256).
subtract
The result of image - imagewindow, with underflow wrapping
around (mod 256). The add and subtract operators can be used to
perform reversible transformations.
difference
The result of abs(image - imagewindow). This is useful for
comparing two very similar images.
bumpmap
The result of imagewindow shaded by window.
replace
The resulting image is imagewindow replaced with image. Here
the matte information is ignored.
The image compositor requires a matte, or alpha channel in the
image for some operations. This extra channel usually defines a
mask which represents a sort of a cookie-cutter for the image.
This is the case when matte is 255 (full coverage) for pixels
inside the shape, zero outside, and between zero and 255 on the
boundary. If image does not have a matte channel, it is
initialized with 0 for any pixel matching in color to pixel
location (0,0), otherwise 255. See Matte Editing for a method of
defining a matte channel.
If you choose blend, the composite operator becomes over. The
image matte channel percent transparency is initialized to
factor. The image window is initialized to (100-factor). Where
factor is the value you specify in the Dialog widget.
Displace shifts the image pixels as defined by a displacement
map. With this option, image is used as a displacement map.
Black, within the displacement map, is a maximum positive
displacement. White is a maximum negative displacement and
middle gray is neutral. The displacement is scaled to determine
the pixel shift. By default, the displacement applies in both
the horizontal and vertical directions. However, if you specify
mask, image is the horizontal X displacement and mask the
vertical Y displacement.
Note that matte information for image window is not retained for
colormapped X server visuals (e.g. StaticColor,StaticColor,GrayScale,PseudoColor). Correct compositing behavior may
require a TrueColor or DirectColor visual or a StandardColormap.
Choosing a composite operator is optional. The default operator
is replace. However, you must choose a location to composite
your image and press button 1. Press and hold the button before
releasing and an outline of the image will appear to help you
identify your location.
The actual colors of the composite image is saved. However, the
color that appears in image window may be different. For
example, on a monochrome screen Image window will appear black
or white even though your composited image may have many colors.
If the image is saved to a file it is written with the correct
colors. To assure the correct colors are saved in the final
image, any PseudoClass image is promoted to DirectClass (see
miff). To force a PseudoClass image to remain PseudoClass, use
-colors.

COLOREDITING

Changing the the color of a set of pixels is performed interactively.
There is no command line argument to edit a pixel. To begin, choose
Color from the ImageEdit submenu of the Command widget.
Alternatively, press c in the image window.
A small window appears showing the location of the cursor in the image
window. You are now in color edit mode. To exit immediately, press
Dismiss. In color edit mode, the Commandwidget has these options:
Method
point
replace
floodfill
reset
PixelColor
black
blue
cyan
green
gray
red
magenta
yellow
white
Browser...
BorderColor
black
blue
cyan
green
gray
red
magenta
yellow
white
Browser...
Fuzz
0
2
4
8
16
Dialog...
UndoHelpDismiss
Choose a color editing method from the Method sub-menu of the Command
widget. The pointmethod recolors any pixel selected with the pointer
unless the button is released. The replacemethod recolors any pixel
that matches the color of the pixel you select with a button press.
Floodfill recolors any pixel that matches the color of the pixel you
select with a button press and is a neighbor. Whereas filltoborder
changes the matte value of any neighbor pixel that is not the border
color. Finally reset changes the entire image to the designated color.
Next, choose a pixel color from the PixelColor sub-menu. Additional
pixel colors can be specified with the color browser. You can change
the menu colors by setting the X resources pen1 through pen9.
Now press button 1 to select a pixel within the Image window to change
its color. Additional pixels may be recolored as prescribed by the
method you choose. additional pixels by increasing the Delta value.
If the Magnifywidget is mapped, it can be helpful in positioning your
pointer within the image (refer to button 2). Alternatively you can
select a pixel to recolor from within the Magnifywidget. Move the
pointer to the Magnifywidget and position the pixel with the cursor
control keys. Finally, press a button to recolor the selected pixel (or
pixels).
The actual color you request for the pixels is saved in the image.
However, the color that appears in your Image window may be different.
For example, on a monochrome screen the pixel will appear black or
white even if you choose the color red as the pixel color. However, the
image saved to a file with -write is written with red pixels. To assure
the correct color text in the final image, any PseudoClass image is
promoted to DirectClass To force a PseudoClass image to remain
PseudoClass, use -colors.

MATTEEDITING

Matte information within an image is useful for some operations such as
image compositing. This extra channel usually defines a mask which
represents a sort of a cookie-cutter for the image. This is the case
when matte is 255 (full coverage) for pixels inside the shape, zero
outside, and between zero and 255 on the boundary.
Setting the matte information in an image is done interactively. There
is no command line argument to edit a pixel. To begin, and choose Matte
of the ImageEdit sub-menu from the Command widget.
Alternatively, press m in the image window.
A small window appears showing the location of the cursor in the image
window. You are now in matte edit mode. To exit immediately, press
Dismiss. In matte edit mode, the Command widget has these options:
Method
point
replace
floodfill
reset
BorderColor
black
blue
cyan
green
gray
red
magenta
yellow
white
Browser...
Fuzz
0
2
4
8
16
Dialog...
MatteUndoHelpDismiss
Choose a matte editing method from the Method sub-menu of the Command
widget. The pointmethod changes the matte value of the any pixel
selected with the pointer until the button is released. The replacemethod changes the matte value of any pixel that matches the color of
the pixel you select with a button press. Floodfill changes the matte
value of any pixel that matches the color of the pixel you select with
a button press and is a neighbor. Whereas filltoborder recolors any
neighbor pixel that is not the border color. Finally reset changes the
entire image to the designated matte value. Choose MatteValue and a
dialog appears requesting a matte value. Enter a value between 0and255. This value is assigned as the matte value of the selected pixel or
pixels. Now, press any button to select a pixel within the Image
window to change its matte value. You can change the matte value of
additional pixels by increasing the Delta value. The Delta value is
first added then subtracted from the red, green, and blue of the target
color. Any pixels within the range also have their matte value updated.
If the Magnifywidget is mapped, it can be helpful in positioning your
pointer within the image (refer to button 2). Alternatively you can
select a pixel to change the matte value from within the Magnifywidget. Move the pointer to the Magnifywidget and position the pixel
with the cursor control keys. Finally, press a button to change the
matte value of the selected pixel (or pixels). Matte information is
only valid in a DirectClassimage. Therefore, any PseudoClass image is
promoted to DirectClass. Note that matte information for PseudoClass is
not retained for colormapped X server visuals (e.g. StaticColor,StaticColor,GrayScale,PseudoColor) unless you immediately save your
image to a file (refer to Write). Correct matte editing behavior may
require a TrueColor or DirectColor visual or a StandardColormap.

IMAGEDRAWING

An image is drawn upon interactively. Thereisnocommandlineargumenttodrawonanimage. To begin, choose Draw of the Image Edit sub-menu
from the Command widget. Alternatively, press d in the image window.
The cursor changes to a crosshair to indicate you are in draw mode. To
exit immediately, press Dismiss. In draw mode, the Command widget has
these options:
Primitive
point
line
rectangle
fill rectangle
circle
fill circle
ellipse
fill ellipse
polygon
fill polygon
Color
black
blue
cyan
green
gray
red
magenta
yellow
white
transparent
Browser...
Stipple
Brick
Diagonal
Scales
Vertical
Wavy
Translucent
Opaque
Open...
Width
1
2
4
8
16
Dialog...
UndoHelpDismiss
Choose a drawing primitive from the Primitive sub-menu.
Next, choose a color from the Color sub-menu. Additional colors can be
specified with the color browser. You can change the menu colors by
setting the X resources pen1 through pen9. The transparent color
updates the image matte channel and is useful for image compositing.
If you choose the color browser and press Grab, you can select the
primitive color by moving the pointer to the desired color on the
screen and press any button. The transparent color updates the image
matte channel and is useful for image compositing.
Choose a stipple, if appropriate, from the Stipple sub-menu. Additional
stipples can be specified with the file browser. Stipples obtained from
the file browser must be on disk in the X11 bitmap format.
Choose a line width, if appropriate, from the Width sub-menu. To choose
a specific width select the Dialog widget.
Choose a point in the image window and press button 1 and hold. Next,
move the pointer to another location in the image. As you move, a line
connects the initial location and the pointer. When you release the
button, the image is updated with the primitive you just drew. For
polygons, the image is updated when you press and release the button
without moving the pointer.
To cancel image drawing, move the pointer back to the starting point of
the line and release the button.

REGIONOFINTEREST

To begin, press choose Region of Interest of the Pixel Transform sub-
menu from the Command widget. Alternatively, press R in the image
window.
A small window appears showing the location of the cursor in the image
window. You are now in region of interest mode. In region of interest
mode, the Command widget has these options:
HelpDismiss
To define a region of interest, press button 1 and drag. The region of
interest is defined by a highlighted rectangle that expands or
contracts as it follows the pointer. Once you are satisfied with the
region of interest, release the button. You are now in apply mode. In
apply mode the Command widget has these options:
File
Save...
Print...
Edit
Undo
Redo
Transform
Flip
Flop
Rotate Right
Rotate Left
Enhance
Hue...
Saturation...
Brightness...
Gamma...
Spiff
Dull
Equalize
Normalize
Negate
GRAYscale
Quantize...
Effects
Despeckle
Emboss
Reduce Noise
Add Noise
Sharpen...
Blur...
Threshold...
Edge Detect...
Spread...
Shade...
Raise...
Segment...
F/X
Solarize...
Swirl...
Implode...
Wave...
Oil Paint
Charcoal Draw...
Miscellany
Image Info
Zoom Image
Show Preview...
Show Histogram
Show Matte
HelpDismiss
You can make adjustments to the region of interest by moving the
pointer to one of the rectangle corners, pressing a button, and
dragging. Finally, choose an image processing technique from the
Command widget. You can choose more than one image processing technique
to apply to an area. Alternatively, you can move the region of interest
before applying another image processing technique. To exit, press
Dismiss.

IMAGEPANNING

When an image exceeds the width or height of the X server screen,
display maps a small panning icon. The rectangle within the panning
icon shows the area that is currently displayed in the the image
window. To pan about the image, press any button and drag the pointer
within the panning icon. The pan rectangle moves with the pointer and
the image window is updated to reflect the location of the rectangle
within the panning icon. When you have selected the area of the image
you wish to view, release the button.
Use the arrow keys to pan the image one pixel up, down, left, or right
within the image window.
The panning icon is withdrawn if the image becomes smaller than the
dimensions of the X server screen.

USERPREFERENCES

Preferences affect the default behavior of display(1). The preferences
are either true or false and are stored in your home directory as
.displayrc:
displayimagecenteredonabackdrop"
.in 20
This backdrop covers the entire workstation screen and is
useful for hiding other X window activity while viewing
the image. The color of the backdrop is specified as the
background color. Refer to X Resources for details.
confirmonprogramexit"
.in 20
Ask for a confirmation before exiting the display(1)
program.
correctimagefordisplaygamma"
.in 20
If the image has a known gamma, the gamma is corrected to
match that of the X server (see the X Resource
displayGamma).
displaywarningmessages"
.in 20
Display any warning messages.
applyFloyd/Steinbergerrordiffusiontoimage"
.in 20
The basic strategy of dithering is to trade intensity
resolution for spatial resolution by averaging the
intensities of several neighboring pixels. Images which
suffer from severe contouring when reducing colors can be
improved with this preference.
useasharedcolormapforcolormappedXvisuals"
.in 20
This option only applies when the default X server visual
is PseudoColor or GRAYScale. Refer to -visual for more
details. By default, a shared colormap is allocated. The
image shares colors with other X clients. Some image
colors could be approximated, therefore your image may
look very different than intended. Otherwise the image
colors appear exactly as they are defined. However, other
clients may go technicolor when the image colormap is
installed.
displayimagesasanXserverpixmap"
.in 20
Images are maintained as a XImage by default. Set this
resource to True to utilize a server Pixmap instead. This
option is useful if your image exceeds the dimensions of
your server screen and you intend to pan the image.
Panning is much faster with Pixmaps than with a XImage.
Pixmaps are considered a precious resource, use them with
discretion.

GMIDENTIFY

Identify describes the format and characteristics of one or more image
files. It will also report if an image is incomplete or corrupt. The
information displayed includes the scene number, the file name, the
width and height of the image, whether the image is colormapped or not,
the number of colors in the image, the number of bytes in the image,
the format of the image (JPEG, PNM, etc.), and finally the number of
seconds it took to read and process the image. An example line output
from identify follows:
images/aquarium.miff 640x480 PseudoClass 256c
308135b MIFF 1s
If -verbose is set, expect additional output including any image
comment:
Image: images/aquarium.miff
class: PseudoClass
colors: 256
signature: eb5dca81dd93ae7e6ffae99a527eb5dca8...
matte: False
geometry: 640x480
depth: 8
bytes: 308135
format: MIFF
comments:
Imported from MTV raster image: aquarium.mtv
For some formats, additional format-specific information about the file
will be written if the -debug coder or -debug all option is used.

IDENTIFYOPTIONS

Options are processed in command line order. Any option you specify on
the command line remains in effect for the set of images immediately
following, until the set is terminated by the appearance of any option
or -noop.
For a more detailed description of each option, see Options, above.
-authenticate<string>
decrypt image with this password
-cache<threshold>
(This option has been replaced by the -limit option)
-debug<events>
enable debug printout
-define<key>{=<value>},...
add coder/decoder specific options
-density<width>x<height>
horizontal and vertical resolution in pixels of the image
-depth<value>
depth of the image
-format<string>
output formatted image characteristics
-help print usage instructions
-interlace<type>
the type of interlacing scheme
-limit<type><value>
Disk, File, Map, or Memory resource limit
-log<string>
Specify format for debug log
-ping efficiently determine image characteristics
-sampling-factor<horizontal_factor>x<vertical_factor>
sampling factors used by JPEG or MPEG-2 encoder and YUV
decoder/encoder.
-size<width>x<height>{+offset}
width and height of the image
-verbose
print detailed information about the image
-version
print GraphicsMagick version string
For a more detailed description of each option, see Options,
above.

GMIMPORT

Import reads an image from any visible window on an X server and
outputs it as an image file. You can capture a single window, the
entire screen, or any rectangular portion of the screen. Use display
for redisplay, printing, editing, formatting, archiving, image
processing, etc. of the captured image.
The target window can be specified by id, name, or may be selected by
clicking the mouse in the desired window. If you press a button and
then drag, a rectangle will form which expands and contracts as the
mouse moves. To save the portion of the screen defined by the
rectangle, just release the button. The keyboard bell is rung once at
the beginning of the screen capture and twice when it completes.

EXAMPLES

To select an X window or an area of the screen with the mouse and save
it in the MIFF image format to a file entitled window.miff, use:
gm import window.miff
To select an X window or an area of the screen with the mouse and save
it in the Encapsulated PostScript format to include in another
document, use:
gm import figure.eps
To capture the entire X server screen in the JPEG image format in a
file entitled root.jpeg, without using the mouse, use:
gm import -window root root.jpeg
To capture the 512x256 area at the upper right corner of the X server
screen in the PNG image format in a well-compressed file entitled
corner.png, without using the mouse, use:
gm import -window root -crop 512x256-0+0 -quality 90
corner.png

OPTIONS

Options are processed in command line order. Any option you specify on
the command line remains in effect until it is explicitly changed by
specifying the option again with a different effect.
Import options can appear on the command line or in your X resources
file. See X(1). Options on the command line supersede values specified
in your X resources file.
For a more detailed description of each option, see Options, above.
-bordercolor<color>
the border color
-cache<threshold>
(This option has been replaced by the -limit option)
-colors<value>
preferred number of colors in the image
-colorspace<value>
the type of colorspace
-comment<string>
annotate an image with a comment
-crop<width>x<height>{+-}<x>{+-}<y>{%}
preferred size and location of the cropped image
-debug<events>
enable debug printout
-define<key>{=<value>},...
add coder/decoder specific options
-delay<1/100thsofasecond>
display the next image after pausing
-density<width>x<height>
horizontal and vertical resolution in pixels of the image
-depth<value>
depth of the image
-descend
obtain image by descending window hierarchy
-display<host:display[.screen]>
specifies the X server to contact
-dispose<method>
GIF disposal method
-dither
apply Floyd/Steinberg error diffusion to the image
-encoding<type>
specify the text encoding
-endian<type>
specify endianness (MSB or LSB) of output image
-frame include the X window frame in the imported image
-geometry<width>x<height>{+-}<x>{+-}<y>{%}{@}{!}{<}{>}
preferred size and location of the Image window.
-help print usage instructions
-interlace<type>
the type of interlacing scheme
-label<name>
assign a label to an image
-limit<type><value>
Disk, File, Map, or Memory resource limit
-log<string>
Specify format for debug log
-monochrome
transform the image to black and white
-negate
replace every pixel with its complementary color
-page<width>x<height>{+-}<x>{+-}<y>{%}{!}{<}{>}
size and location of an image canvas
-pause<seconds>
pause between snapshots [import]
-ping efficiently determine image characteristics
-pointsize<value>
pointsize of the PostScript, OPTION1, or TrueType font
-quality<value>
JPEG/MIFF/PNG compression level
-resize<width>x<height>{%}{@}{!}{<}{>}
resize an image
-rotate<degrees>{<}{>}
apply Paeth image rotation to the image
-sampling-factor<horizontal_factor>x<vertical_factor>
sampling factors used by JPEG or MPEG-2 encoder and YUV
decoder/encoder.
-scene<value>
set scene number
-screen
specify the screen to capture
-silent
operate silently
-snaps<value>
number of screen snapshots
-transparent<color>
make this color transparent within the image
-trim trim an image
-verbose
print detailed information about the image
-version
print GraphicsMagick version string
For a more detailed description of each option, see Options,
above.

GMMOGRIFY

Mogrify transforms an image or a sequence of images. These transforms
include image scaling, image rotation, color reduction, and others.
Each transmogrified image overwrites the corresponding original image,
unless an option such as -format causes the output filename to be
different from the input filename.
The graphics formats supported by mogrify are listed in
GraphicsMagick(1).

EXAMPLES

To convert all the TIFF files in a particular directory to JPEG, use:
gm mogrify -format jpeg *.tiff
To convert a directory full of JPEG images to thumbnails, use:
gm mogrify -size 120x120 *.jpg -resize 120x120 +profile "*"
In this example, ’-size 120x120’ gives a hint to the JPEG decoder that
the images are going to be downscaled to 120x120, allowing it to run
faster by avoiding returning full-resolution images to GraphicsMagick
for the subsequent resizing operation. The ´-resize 120x120’ specifies
the desired dimensions of the output images. It will be scaled so its
largest dimension is 120 pixels. The ´+profile "*"’ removes any ICM,
EXIF, IPTC, or other profiles that might be present in the input and
aren’t needed in the thumbnails.
To scale an image of a cockatoo to exactly 640 pixels in width and 480
pixels in height, use:
gm mogrify -resize 640x480! cockatoo.miff

OPTIONS

Options are processed in command line order. Any option you specify on
the command line remains in effect for the set of images that follows,
until the set is terminated by the appearance of any option or -noop.
For a more detailed description of each option, see Options, above.
-affine<matrix>
drawing transform matrix
-antialias
remove pixel aliasing
-authenticate<string>
decrypt image with this password
-background<color>
the background color
-blue-primary<x>,<y>
blue chromaticity primary point
-blur<radius>{x<sigma>}
blur the image with a Gaussian operator
-border<width>x<height>
surround the image with a border of color
-bordercolor<color>
the border color
-cache<threshold>
(This option has been replaced by the -limit option)
-channel<type>
the type of channel
-charcoal<factor>
simulate a charcoal drawing
-colorize<value>
colorize the image with the pen color
-colors<value>
preferred number of colors in the image
-colorspace<value>
the type of colorspace
-comment<string>
annotate an image with a comment
-compose<operator>
the type of image composition
-compress<type>
the type of image compression
-contrast
enhance or reduce the image contrast
-convolve<kernel>
convolve image with the specified convolution kernel
-crop<width>x<height>{+-}<x>{+-}<y>{%}
preferred size and location of the cropped image
-cycle<amount>
displace image colormap by amount
-debug<events>
enable debug printout
-define<key>{=<value>},...
add coder/decoder specific options
-delay<1/100thsofasecond>
display the next image after pausing
-density<width>x<height>
horizontal and vertical resolution in pixels of the image
-depth<value>
depth of the image
-despeckle
reduce the speckles within an image
-display<host:display[.screen]>
specifies the X server to contact
-dispose<method>
GIF disposal method
-dither
apply Floyd/Steinberg error diffusion to the image
-draw<string>
annotate an image with one or more graphic primitives
-edge<radius>
detect edges within an image
-emboss<radius>
emboss an image
-encoding<type>
specify the text encoding
-endian<type>
specify endianness (MSB or LSB) of output image
-enhance
apply a digital filter to enhance a noisy image
-equalize
perform histogram equalization to the image
-fill<color>
color to use when filling a graphic primitive
-filter<type>
use this type of filter when resizing an image
-flip create a "mirror image"
-flop create a "mirror image"
-font<name>
use this font when annotating the image with text
-format<type>
the image format type
-frame<width>x<height>+<outerbevelwidth>+<innerbevelwidth>
surround the image with an ornamental border
-fuzz<distance>{%}
colors within this distance are considered equal
-gamma<value>
level of gamma correction
-Gaussian<radius>{x<sigma>}
blur the image with a Gaussian operator
-geometry<width>x<height>{+-}<x>{+-}<y>{%}{@}{!}{<}{>}
preferred size and location of the Image window.
-gravity<type>
direction primitive gravitates to when annotating the image.
-green-primary<x>,<y>
green chromaticity primary point
-help print usage instructions
-implode<factor>
implode image pixels about the center
-interlace<type>
the type of interlacing scheme
-label<name>
assign a label to an image
-lat<width>x<height>{+-}<offset>{%}
perform local adaptive thresholding
-level<black_point>{,<gamma>}{,<white_point>}{%}
adjust the level of image contrast
-limit<type><value>
Disk, File, Map, or Memory resource limit
-linewidth
the line width for subsequent draw operations
-list<type>
the type of list
-log<string>
Specify format for debug log
-loop<iterations>
add Netscape loop extension to your GIF animation
-map<filename>
choose a particular set of colors from this image
-mask<filename>
Specify a clipping mask
-matte store matte channel if the image has one
-mattecolor<color>
specify the color to be used with the -frame option
-median<radius>
apply a median filter to the image
-modulatebrightness[,saturation[,hue]]
vary the brightness, saturation, and hue of an image
-monochrome
transform the image to black and white
-negate
replace every pixel with its complementary color
-noise<radius|type>
add or reduce noise in an image
-noop NOOP (no option)
-normalize
transform image to span the full range of color values
-opaque<color>
change this color to the pen color within the image
-operatorchanneloperatorrvalue[%]
apply a mathematical or bitwise operator to an image channel
-ordered-dither<channeltype><NxN>
ordered dither the image
-page<width>x<height>{+-}<x>{+-}<y>{%}{!}{<}{>}
size and location of an image canvas
-paint<radius>
simulate an oil painting
-pen<color>
(This option has been replaced by the -fill option)
-pointsize<value>
pointsize of the PostScript, OPTION1, or TrueType font
-profile<filename>
add ICM, IPTC, or generic profile to image
-quality<value>
JPEG/MIFF/PNG compression level
-raise<width>x<height>
lighten or darken image edges
-random-threshold<channeltype><LOWxHIGH>
random threshold the image
-red-primary<x>,<y>
red chromaticity primary point
-region<width>x<height>{+-}<x>{+-}<y>
apply options to a portion of the image
-render
render vector operations
-resample<horizontal>x<vertical>
Resample image to specified horizontal and vertical resolution
-resize<width>x<height>{%}{@}{!}{<}{>}
resize an image
-roll{+-}<x>{+-}<y>
roll an image vertically or horizontally
-rotate<degrees>{<}{>}
apply Paeth image rotation to the image
-sample<geometry>
scale image using pixel sampling
-sampling-factor<horizontal_factor>x<vertical_factor>
sampling factors used by JPEG or MPEG-2 encoder and YUV
decoder/encoder.
-scale<geometry>
scale the image.
-scene<value>
set scene number
-segment<clusterthreshold>x<smoothingthreshold>
segment an image
-shade<azimuth>x<elevation>
shade the image using a distant light source
-sharpen<radius>{x<sigma>}
sharpen the image
-shave<width>x<height>{%}
shave pixels from the image edges
-shear<xdegrees>x<ydegrees>
shear the image along the X or Y axis
-size<width>x<height>{+offset}
width and height of the image
-solarize<factor>
negate all pixels above the threshold level
-spread<amount>
displace image pixels by a random amount
-stroke<color>
color to use when stroking a graphic primitive
-strokewidth<value>
set the stroke width
-swirl<degrees>
swirl image pixels about the center
-texture<filename>
name of texture to tile onto the image background
-threshold<value>{<green>,<blue>,<opacity>}{%}
threshold the image
-tile<filename>
tile image when filling a graphic primitive
-transform
transform the image
-transparent<color>
make this color transparent within the image
-treedepth<value>
tree depth for the color reduction algorithm
-trim trim an image
-type<type>
the image type
-units<type>
the units of image resolution
-unsharp<radius>{x<sigma>}{+<amount>}{+<threshold>}
sharpen the image with an unsharp mask operator
-verbose
print detailed information about the image
-version
print GraphicsMagick version string
-view<string>
FlashPix viewing parameters
-virtual-pixel<method>
specify contents of "virtual pixels"
-wave<amplitude>x<wavelength>
alter an image along a sine wave
-white-point<x>,<y>
chromaticity white point
For a more detailed description of each option, see Options,
above.

GMMONTAGE

montage creates a composite image by combining several separate images.
The images are tiled on the composite image with the name of the image
optionally appearing just below the individual tile.
The composite image is constructed in the following manner. First, each
image specified on the command line, except for the last, is scaled to
fit the maximum tile size. The maximum tile size by default is 120x120.
It can be modified with the -geometry command line argument or X
resource. See Options for more information on command line arguments.
See X(1) for more information on X resources. Note that the maximum
tile size need not be a square.
Next the composite image is initialized with the color specified by the
-background command line argument or X resource. The width and height
of the composite image is determined by the title specified, the
maximum tile size, the number of tiles per row, the tile border width
and height, the image border width, and the label height. The number of
tiles per row specifies how many images are to appear in each row of
the composite image. The default is to have 5 tiles in each row and 4
tiles in each column of the composite. A specific value is specified
with -tile. The tile border width and height, and the image border
width defaults to the value of the X resource -borderwidth. It can be
changed with the -borderwidth or -geometry command line argument or X
resource. The label height is determined by the font you specify with
the -font command line argument or X resource. If you do not specify a
font, a font is chosen that allows the name of the image to fit the
maximum width of a tiled area. The label colors is determined by the
-background and -fill command line argument or X resource. Note, that
if the background and pen colors are the same, labels will not appear.
Initially, the composite image title is placed at the top if one is
specified (refer to -fill). Next, each image is set onto the composite
image, surrounded by its border color, with its name centered just
below it. The individual images are left-justified within the width of
the tiled area. The order of the images is the same as they appear on
the command line unless the images have a scene keyword. If a scene
number is specified in each image, then the images are tiled onto the
composite in the order of their scene number. Finally, the last
argument on the command line is the name assigned to the composite
image. By default, the image is written in the MIFF format and can be
viewed or printed with display(1).
Note, that if the number of tiles exceeds the default number of 20 (5
per row, 4 per column), more than one composite image is created. To
ensure a single image is produced, use -tile to increase the number of
tiles to meet or exceed the number of input images.
Finally, to create one or more empty spaces in the sequence of tiles,
use the "NULL:" image format.
Note, a composite MIFF image displayed to an X server with display
behaves differently than other images. You can think of the composite
as a visual image directory. Choose a particular tile of the composite
and press a button to display it. See display(1) and miff(5)

EXAMPLES

To create a montage of a cockatoo, a parrot, and a hummingbird and
write it to a file called birds, use:
gm montage cockatoo.miff parrot.miff hummingbird.miff
birds.miff
To tile several bird images so that they are at most 256 pixels in
width and 192 pixels in height, surrounded by a red border, and
separated by 10 pixels of background color, use:
gm montage -geometry 256x192+10+10 -bordercolor red
birds.* montage.miff
To create an unlabeled parrot image, 640 by 480 pixels, and surrounded
by a border of black, use:
gm montage -geometry 640x480 -bordercolor black
-label "" parrot.miff bird.miff
To create an image of an eagle with a textured background, use:
gm montage -texture bumps.jpg eagle.jpg eagle.png
To join several GIF images together without any extraneous graphics
(e.g. no label, no shadowing, no surrounding tile frame), use:
gm montage +frame +shadow +label -tile 5x1
-geometry 50x50+0+0 *.png joined.png

OPTIONS

Any option you specify on the command line remains in effect for the
group of images following it, until the group is terminated by the
appearance of any option or -noop. For example, to make a montage of
three images, the first with 32 colors, the second with an unlimited
number of colors, and the third with only 16 colors, use:
gm montage -colors 32 cockatoo.1 -noop cockatoo.2
-colors 16 cockatoo.3 cockatoos.miff
For a more detailed description of each option, see Options, above.
-adjoin
join images into a single multi-image file
-authenticate<string>
decrypt image with this password
-background<color>
the background color
-blue-primary<x>,<y>
blue chromaticity primary point
-blur<radius>{x<sigma>}
blur the image with a Gaussian operator
-bordercolor<color>
the border color
-borderwidth<geometry>
the border width
-cache<threshold>
(This option has been replaced by the -limit option)
-chop<width>x<height>{+-}<x>{+-}<y>{%}
remove pixels from the interior of an image
-colors<value>
preferred number of colors in the image
-colorspace<value>
the type of colorspace
-comment<string>
annotate an image with a comment
-compose<operator>
the type of image composition
-compress<type>
the type of image compression
-crop<width>x<height>{+-}<x>{+-}<y>{%}
preferred size and location of the cropped image
-debug<events>
enable debug printout
-define<key>{=<value>},...
add coder/decoder specific options
-density<width>x<height>
horizontal and vertical resolution in pixels of the image
-depth<value>
depth of the image
-display<host:display[.screen]>
specifies the X server to contact
-dispose<method>
GIF disposal method
-dither
apply Floyd/Steinberg error diffusion to the image
-draw<string>
annotate an image with one or more graphic primitives
-encoding<type>
specify the text encoding
-endian<type>
specify endianness (MSB or LSB) of output image
-fill<color>
color to use when filling a graphic primitive
-filter<type>
use this type of filter when resizing an image
-font<name>
use this font when annotating the image with text
-frame<width>x<height>+<outerbevelwidth>+<innerbevelwidth>
surround the image with an ornamental border
-gamma<value>
level of gamma correction
-geometry<width>x<height>{+-}<x>{+-}<y>{%}{@}{!}{<}{>}
preferred size and location of the Image window.
-gravity<type>
direction primitive gravitates to when annotating the image.
-green-primary<x>,<y>
green chromaticity primary point
-help print usage instructions
-interlace<type>
the type of interlacing scheme
-label<name>
assign a label to an image
-limit<type><value>
Disk, File, Map, or Memory resource limit
-log<string>
Specify format for debug log
-matte store matte channel if the image has one
-mattecolor<color>
specify the color to be used with the -frame option
-mode<value>
mode of operation
-monochrome
transform the image to black and white
-noop NOOP (no option)
-page<width>x<height>{+-}<x>{+-}<y>{%}{!}{<}{>}
size and location of an image canvas
-pen<color>
(This option has been replaced by the -fill option)
-pointsize<value>
pointsize of the PostScript, OPTION1, or TrueType font
-quality<value>
JPEG/MIFF/PNG compression level
-red-primary<x>,<y>
red chromaticity primary point
-render
render vector operations
-resize<width>x<height>{%}{@}{!}{<}{>}
resize an image
-rotate<degrees>{<}{>}
apply Paeth image rotation to the image
-sampling-factor<horizontal_factor>x<vertical_factor>
sampling factors used by JPEG or MPEG-2 encoder and YUV
decoder/encoder.
-scenes<value-value>
range of image scene numbers to read
-shadow<radius>{x<sigma>}
shadow the montage
-sharpen<radius>{x<sigma>}
sharpen the image
-size<width>x<height>{+offset}
width and height of the image
-stroke<color>
color to use when stroking a graphic primitive
-strokewidth<value>
set the stroke width
-texture<filename>
name of texture to tile onto the image background
-tile<geometry>
layout of images [montage]
-title<string>
assign title to displayed image [animate,display,montage]
-transparent<color>
make this color transparent within the image
-treedepth<value>
tree depth for the color reduction algorithm
-trim trim an image
-type<type>
the image type
-verbose
print detailed information about the image
-version
print GraphicsMagick version string
-white-point<x>,<y>
chromaticity white point
For a more detailed description of each option, see Options,
above.

XRESOURCES

Montage options can appear on the command line or in your X resource
file. Options on the command line supersede values specified in your X
resource file. See X(1) for more information on X resources.
All montage options have a corresponding X resource. In addition,
montage uses the following X resources:
background(classBackground)
background color
Specifies the preferred color to use for the composite image
background. The default is #ccc.
borderColor(classBorderColor)
border color
Specifies the preferred color to use for the composite image
border. The default is #ccc.
borderWidth(classBorderWidth)
border width
Specifies the width in pixels of the composite image border. The
default is 2.
font(classFont)
font to use
Specifies the name of the preferred font to use when displaying
text within the composite image. The default is 9x15, fixed, or
5x8 determined by the composite image size.
matteColor(classMatteColor)
color of the frame
Specify the color of an image frame. A 3D effect is achieved by
using highlight and shadow colors derived from this color. The
default value is #697B8F.
pen(classPen)
text color
Specifies the preferred color to use for text within the
composite image. The default is black.
title(classTitle)
composite image title
This resource specifies the title to be placed at the top of the
composite image. The default is not to place a title at the top
of the composite image.

ENVIRONMENT

COLUMNS
Output screen width. Used when formatting text for the screen.
Many Unix systems keep this shell variable up to date, but it
may need to be explicitly exported in order for GraphicsMagick
to see it.
DISPLAY
X11 display ID (host, display number, and screen in the form
hostname:display.screen).
HOME Location of user’s home directory. GraphicsMagick searches for
configuration files in $HOME/.magick if the directory exists.
See MAGICK_CODER_MODULE_PATH, MAGICK_CONFIGURE_PATH, and
MAGICK_FILTER_MODULE_PATH if more flexibility is needed.
MAGICK_CODER_MODULE_PATH
Search path to use when searching for image format coder
modules. This path allows the user to arbitrarily extend the
image formats supported by GraphicsMagick by adding loadable
modules to an arbitrary location rather than copying them into
the GraphicsMagick installation directory. The formatting of the
search path is similar to operating system search paths (i.e.
colon delimited for Unix, and semi-colon delimited for Microsoft
Windows). This user specified search path is used before trying
the default search path.
MAGICK_CONFIGURE_PATH
Search path to use when searching for configuration (.mgk)
files. The formatting of the search path is similar to
operating system search paths (i.e. colon delimited for Unix,
and semi-colon delimited for Microsoft Windows). This user
specified search path is used before trying the default search
path.
MAGICK_DEBUG
Debug options (see -debug for details)
MAGICK_FILTER_MODULE_PATH
Search path to use when searching for filter process modules
(invoked via -process). This path allows the user to arbitrarily
extend GraphicsMagick’s image processing functionality by adding
loadable modules to an arbitrary location rather than copying
them into the GraphicsMagick installation directory. The
formatting of the search path is similar to operating system
search paths (i.e. colon delimited for Unix, and semi-colon
delimited for Microsoft Windows). This user specified search
path is used before trying the default search path.
MAGICK_HOME
Path to top of GraphicsMagick installation directory. Only
observed by "uninstalled" builds of GraphicsMagick which do not
have their location hard-coded or set by an installer.
MAGICK_LIMIT_DISK
Maximum amount of disk space allowed for use by the pixel cache.
MAGICK_LIMIT_FILES
Maximum number of open files.
MAGICK_LIMIT_MAP
Maximum size of a memory map.
MAGICK_LIMIT_MEMORY
Maximum amount of memory to allocate from the heap.
MAGICK_TMPDIR
Path to directory where GraphicsMagick should write temporary
files. The default is to use the system default, or the location
set by TMPDIR.
TMPDIR For POSIX-compatible systems (Unix-compatible), the path to the
directory where all applications should write temporary files.
Overridden by MAGICK_TMPDIR if it is set.
TMPorTEMP
For Microsoft Windows, the path to the directory where
applications should write temporary files. Overridden by
MAGICK_TMPDIR if it is set.

ACKNOWLEDGEMENTS

The MITXConsortium for making network transparent graphics a reality.
MichaelHalle, SpatialImagingGroupatMIT, for the initial
implementation of Alan Paeth’s image rotation algorithm.
DavidPensak, E.I.duPontdeNemoursandCompany, for providing a
computing environment that made this program possible.
PederLanglo, HewlettPackard, Norway, made hundreds of suggestions and
bug reports. Without Peder, this software would not be nearly as useful
as it is today.
RodBogart and JohnW.Peterson, UniversityofUtah. Image compositing
is loosely based on rlecomp of the Utah Raster Toolkit.
PaulHeckbert, CarnegieMellonUniversity. Image resizing is based on
his Zoom program.
PaulRaveling, USCInformationSciencesInstitute. The spatial
subdivision color reduction algorithm is based on his Img software.